How Animals Sleep: A Field Guide to Sleep Postures and Positions

Sleep appears across the animal kingdom in forms that range from the familiar to the startling. A horse dozing on its feet, a bat hanging head down, a fur seal sleeping with one half of its brain awake, and a shark resting flat on the seafloor all represent solutions to the same biological demands. This field guide categorizes the major sleep postures observed in animals, explains the evolutionary and ecological reasons behind each position, and provides practical guidance for observing and recording sleep behavior in domestic and wild settings. The content is intended for students, researchers, life-science professionals, and informed general readers who want a structured approach to understanding why animals sleep the way they do.

At a Glance: Sleep Posture Categories

The table below summarizes the primary sleep postures observed across animal groups, the species most associated with each posture, and the primary functional reasons proposed in the scientific literature.

The Evolutionary Foundations of Sleep Posture

Sleep posture is not random behavior. It reflects millions of years of evolutionary pressure shaped by predation risk, thermoregulatory demands, respiratory requirements, and social context. Understanding these foundations helps explain why a farmer sees a horse standing at rest while a dog curls into a ball and a cat sprawls on its back.

From Reptilian Rest to Mammalian Sleep

The evolutionary pathway from reptilian rest to mammalian sleep offers a framework for understanding posture. One proposed model suggests that the active state of reptiles represents a form of subcortical waking that lacks the cortical waking seen in mammals. According to this view, reptilian waking gave rise to mammalian sleep, and specific reptilian behaviors evolved into distinct sleep states. Reptilian basking behavior is proposed to have evolved into non-rapid eye movement sleep, while post-basking risk assessment behavior with motor suspension, head dipping movements, eye scanning, and stretch attending postures evolved into phasic rapid eye movement sleep. Post-basking goal directed behavior evolved into tonic REM sleep, and nocturnal rest evolved into shallow torpor. This model, presented in Evolution of wakefulness, sleep and hibernation: from reptiles to mammals, suggests that a small number of changes from previous reptilian stages explain the transformations observed in mammalian sleep architecture.

The practical implication is that sleep postures carry evolutionary information. When a reptile assumes a flat posture with limbs splayed, it may be engaging in thermoregulatory basking that has deep evolutionary connections to mammalian sleep states. When a mammal curls into a compact ball, it may be expressing a posture that evolved from ancestral risk assessment behavior.

Ecological Factors Shaping Reptilian Sleep

Reptilian sleep remains understudied compared to mammalian sleep, but ecological factors appear to play a strong role. A systematic review of sleep in non-avian reptiles identifies habitat selection, individual-level traits such as behavior and morphology, and inter-individual interactions as key areas of investigation. The review notes that predation, competition, and thermoregulation likely influence sleep traits and their evolutionary consequences for reptile sociality, morphological specialization, and habitat partitioning. The authors also examine how sleep ecology interacts with urbanization, biological invasions, and climate change, as documented in The ecology of sleep in non-avian reptiles.

For field observers, this means that reptile sleep posture should be interpreted within its ecological context. A lizard sleeping on an exposed branch versus one wedged into a crevice is making different tradeoffs between thermoregulatory access and predation risk. Recording the microhabitat of a sleeping reptile is as important as recording the posture itself.

Standing Sleep: The Posture of Readiness

Standing sleep is among the most recognizable animal sleep postures because it is common in domestic livestock. Horses, cattle, and elephants can all be observed resting while standing, and this posture has clear functional advantages for large herbivores that need to flee predators quickly.

The Biomechanics of Standing Rest

The ability to sleep while standing depends on anatomical adaptations that allow joint locking. The stay apparatus in horses and other ungulates permits the animal to maintain a standing position with minimal muscular effort. This is not a complete loss of consciousness but rather a state of quiet wakefulness or light sleep that allows rapid arousal. The reticulospinal system, which integrates descending instructions for movement execution, plays a role in postural adjustments and sleep atonia. The pontomedullary reticular formation is a key site responsible for integrating descending instructions to execute particular movements, with direct monosynaptic connections to spinal interneurons and motoneurons. Its roles include postural adjustments, walking, and sleep atonia, as reviewed in Reticulospinal Systems for Tuning Motor Commands.

For farmers and animal handlers, the distinction between standing rest and true recumbent sleep matters. A horse standing with a relaxed lower lip, slightly closed eyes, and a lowered head is likely in a state of quiet wakefulness or light slow wave sleep. This state allows the animal to respond quickly to threats but does not provide the full restorative benefits of recumbent REM sleep.

Management Implications for Standing Sleepers

Horses and cattle that stand for extended periods without lying down may be experiencing discomfort or pain. The time budget of horses can serve as a welfare indicator. Research on 174 horses across eight facilities found that time spent feeding, in exploratory walking, and in observation behavior correlated with indicators of positive welfare, while time spent standing immobile resting or in fixed attention correlated with negative welfare indicators. The study suggests that three sessions of 10 minutes of observation, conducted when animals are calm, can provide a good account of the local atmosphere, as reported in Farm Atmosphere: Calm Attention and Mobility Characterise Positive Horse Welfare.

A practical assessment protocol for standing sleep in livestock includes the following steps:

1. Observe the herd or group for 10 minutes during a quiet period, such as mid-morning or early afternoon.
2. Record the number of animals standing immobile versus lying down.
3. Note the posture of standing animals, including head position, ear orientation, and eye closure.
4. Compare observations across multiple days to establish a baseline time budget.
5. Escalate to veterinary assessment if an animal stands continuously for more than 24 hours or shows signs of reluctance to lie down.

Continuous standing without recumbency can indicate lameness, respiratory disease, or gastric ulceration. Horses with equine gastric ulcer syndrome are often presented to veterinarians with a history of problem behaviors, some of which resolve following gastroprotectant therapy. However, problem behaviors persist in some cases despite gastroscopic resolution of disease, and some horses develop pain-related learned anticipatory behavior even after the original source of pain has resolved. Such cases can benefit from a behavioral medicine approach that includes management of underlying diseases, environmental modification, behavior modification, and in select cases behavior-modifying medication, as discussed in Incorporating a Behavioral Medicine Approach in the Multi-Modal Management of Chronic Equine Gastric Ulcer Syndrome.

Upside Down Sleep: The Bat Posture

Bats are the most famous upside down sleepers, and their posture raises immediate questions about blood flow, muscle fatigue, and evolutionary rationale.

Biomechanical Hypotheses for Hanging

The biomechanical hypothesis for why bats hang upside down was formally proposed in the 1970s. The hypothesis considers the energetic costs and benefits of the hanging posture relative to roosting upright. The paper titled Why bats hang upside down: a biomechanical hypothesis presents the mechanical reasoning behind this distinctive posture, though the full abstract is not available in the approved evidence packet.

The hanging posture allows bats to take flight by simply releasing their grip and falling into the air. This is energetically efficient compared to launching from a standing position on a horizontal surface. The posture also places the bat in a position that is difficult for many predators to access, particularly ground-based predators.

Blood Flow and the Head Down Position

The head down position has been the subject of evolutionary speculation beyond bats. A working hypothesis proposes that the head down position of the anthropoid fetus, resulting from maternal upright and semi-upright posture, may have caused physiological craniovascular hypertension that stimulated expansion of the intracranial vessels. This epigenetic physiological stress may have enhanced neurogenesis and contributed to progressive growth of the anthropoid brain. The hypothesis also suggests that brain size in anthropoids may vary according to the degree of exposure of the fetus to postural verticality, as presented in Fetal head-down posture may explain the rapid brain evolution in humans and other primates.

This research is speculative and focused on fetal development instead of sleep posture, but it illustrates that head down positioning has physiological consequences that extend beyond simple gravity tolerance. For bats, the hanging posture is maintained through tendon locking mechanisms that require minimal muscular energy, allowing the bat to remain suspended for hours without fatigue.

Observing Bats in Roost

Field observation of bat sleep requires attention to roost selection and posture. Bats may hang singly or in clusters, and the choice of roost site affects thermoregulatory costs. A bat hanging in a warm roost with high humidity expends less energy maintaining body temperature than one in a cold, dry roost. The popular children's book Bat Loves the Night describes bat behavior for young readers, but researchers should rely on systematic observation protocols.

When recording bat sleep posture, note the following variables:

1. Roost type and height above ground
2. Cluster size and spacing between individuals
3. Wing position, whether wrapped around the body or partially extended
4. Ear position and any visible eye opening
5. Time of day and ambient temperature

Unihemispheric Sleep: Sleeping with Half a Brain

Some animals sleep with only one brain hemisphere at a time. This phenomenon, called unihemispheric slow wave sleep, allows the animal to maintain movement, keep one eye open, and continue breathing while part of the brain rests.

The Fur Seal Model

The northern fur seal provides a striking example of unihemispheric sleep adaptations. As a semiaquatic pinniped, the fur seal must inhabit both land and water environments. Its sleep patterns include unihemispheric slow wave sleep, the ability to maintain movement for stabilization of sleep posture, and the capacity to briefly open one eye while having a sleep electroencephalogram in one hemisphere. In vivo microdialysis studies suggest that acetylcholine release is required for cortical activation during unihemispheric slow wave sleep, while monoamines are not required. The need to breathe, maintain efficient thermoregulation, and avoid predation have shaped sleep patterns in semiaquatic fur seals as in fully aquatic cetaceans, as documented in Sleep in the northern fur seal.

For researchers studying sleep electrophysiology, the fur seal demonstrates that sleep is not a uniform brain state. The ability to keep one hemisphere awake while the other sleeps allows the animal to continue swimming, monitor its environment, and surface for air.

Cetacean Sleep

Fully aquatic cetaceans face a unique challenge: they must breathe at the surface but sleep in water. Unihemispheric sleep allows dolphins and whales to continue swimming while one brain hemisphere rests. This adaptation ensures that the animal can surface to breathe without waking fully.

The practical implication for marine mammal observers is that a swimming dolphin with one eye closed may be sleeping. The closed eye typically corresponds to the awake hemisphere, with the open eye monitoring the environment. This pattern of eye closure during unihemispheric sleep has been documented in fur seals and is likely present in cetaceans.

Flat Recumbency: The Energy Conservation Posture

Flat body posture during sleep is associated with energy conservation and postural relaxation. This posture is common in mammals, reptiles, and even sharks.

Sleep in Sharks

Sharks represent the earliest group of jawed vertebrates and may provide insight into the evolution of sleep. Research on draughtsboard sharks found that lower metabolic rate and a flat body posture reflect sleep, while eye closure is a poorer indication of sleep. The study compared metabolic rates during periods ostensibly thought to be sleep, along with restful and actively swimming sharks across a 24 hour period. The results support the idea that energy conservation is a function of sleep in these basal vertebrates, as reported in Energy conservation characterizes sleep in sharks.

The challenge of identifying sleep in sharks that must swim continuously to breathe is significant. For buccal pumping sharks with clear rest and activity cycles, sleep manifests as behavioral shutdown, postural relaxation, reduced responsiveness, and lowered metabolic rate. However, these features do not lend themselves well to animals that swim nonstop. An electrophysiological study of draughtsboard sharks found that muscle tone was strongest during active wakefulness, lower in quietly awake sharks, and lowest in sleeping sharks. The study also offered suggestions for improving techniques for characterizing sleep electrophysiology in elasmobranchs, particularly for those that swim continuously, as documented in An electrophysiological correlate of sleep in a shark.

Reptilian Recumbency

Reptiles exhibit a range of sleep postures that reflect their ecological context. A flat posture with limbs splayed may serve thermoregulatory functions, allowing the animal to absorb heat from a warm surface. Conversely, a curled posture may conserve heat in cooler conditions. The ecological review of reptilian sleep emphasizes that habitat selection, individual traits, and inter-individual interactions all shape sleep characteristics, as discussed in The ecology of sleep in non-avian reptiles.

For herpetologists and field researchers, recording the substrate temperature and type when observing a sleeping reptile is essential. A lizard sleeping on a rock in the sun is making a different thermoregulatory choice than one sleeping in leaf litter.

On the Back: The Vulnerability Posture

Sleeping on the back exposes the ventral surface, which is among the most vulnerable areas of the body. This posture is therefore most common in animals that feel safe in their environment.

Domestic Dogs and Cats

Domestic dogs and cats frequently sleep on their backs, exposing their bellies. This posture indicates a high level of comfort and perceived safety. In a home environment where predators are absent and social bonds are strong, the vulnerability of the ventral surface is an acceptable risk.

The posture also serves thermoregulatory functions. The ventral surface has less fur than the dorsal surface in many species, allowing heat dissipation when the animal is warm. A dog sleeping on its back with legs spread is likely trying to cool down.

Primate Sleep Postures

Primates show considerable variation in sleep posture. Some monkeys and lesser apes sleep upright, while non-human great apes sleep in horizontal nests. The fetal head down hypothesis suggests that habitual vertical torso posture in monkeys and lesser apes may have physiological consequences for brain development, while the horizontal nest sleeping of great apes may be energetically efficient and related to their larger body mass, as discussed in Fetal head-down posture may explain the rapid brain evolution in humans and other primates.

For primatologists, sleep posture provides information about habitat use and predation risk. A primate sleeping on its back in an exposed position is likely in a low risk environment, while one sleeping curled in a tree fork is responding to higher perceived danger.

Hibernation and Torpor Postures

Hibernation and torpor represent extreme forms of sleep related energy conservation. The postures associated with these states minimize heat loss and metabolic demand.

The Evolution of Hibernation

The evolutionary model that traces mammalian vigilance states from reptilian ancestors proposes that nocturnal rest evolved into shallow torpor. This suggests that hibernation is not a separate phenomenon but rather an extension of the sleep wake continuum. The model, presented in Evolution of wakefulness, sleep and hibernation: from reptiles to mammals, proposes that the active state of reptiles is a form of subcortical waking without homology with the cortical waking of mammals, and that reptilian waking gave origin to mammalian sleep.

Observing Hibernating Animals

When observing hibernating animals, the posture is typically curled with the head tucked and limbs drawn close to the body. This posture minimizes surface area and reduces heat loss. Body temperature drops dramatically, and metabolic rate falls to a fraction of normal levels.

For wildlife researchers, recording the posture of hibernating animals requires minimal disturbance. Approaching a hibernaculum can cause arousal, which expends critical energy reserves. Observation should be conducted from a distance with minimal light and noise.

Sleep Posture and Human Health Connections

The study of animal sleep postures has implications for understanding human sleep disorders. Obstructive sleep apnea has been framed within evolutionary, psychosomatic, and cultural dimensions, with examination of how human bipedalism and sleep posture may predispose to the condition. The reflective travelogue in A journey within: Reflections on sleep apnea, evolution, and the mind-body axis in sleep medicine draws parallels between animal observations and ancient traditions, and critiques CPAP therapy as effective yet mechanistic while envisioning integrative approaches that combine modern science with mindfulness, yoga, and chronobiological practices.

This connection between animal posture and human sleep health is speculative but instructive. The position of the body during sleep affects airway patency, and understanding how different species manage respiratory demands during sleep may inform approaches to human sleep disorders.

Practical Field Observation Protocol

Observing and recording animal sleep postures requires a systematic approach. The following protocol is designed for students, researchers, and life-science professionals.

Equipment and Preparation

1. Binoculars for observing wild animals from a distance
2. Field notebook or digital recording device
3. Thermometer for recording ambient and substrate temperature
4. Camera with zoom capability for photographic documentation
5. Timer for recording observation duration
6. Species identification guide for the study area

Observation Steps

1. Identify the target species and its typical sleep sites.
2. Approach the observation site quietly and maintain a distance that does not disturb the animal.
3. Record the time of day, weather conditions, and ambient temperature.
4. Observe the animal for a minimum of 10 minutes before recording sleep posture.
5. Record the posture using standardized categories: standing, lying on side, lying on back, curled, hanging, floating, or flat.
6. Note the position of the head, limbs, tail, and eyes.
7. Record any movements during the observation period.
8. Note the substrate and its temperature.
9. Record social context, including proximity to other animals.
10. Repeat observations at different times of day across multiple days.

Recording Forms

Use a standardized form with the following fields:

Common Failure Patterns in Sleep Observation

Field observation of animal sleep is prone to several common errors. Recognizing these failure patterns improves data quality.

Misidentifying Quiet Wakefulness as Sleep

Many animals rest quietly without sleeping. A horse standing with eyes closed may be in a state of quiet wakefulness instead of true sleep. The distinction requires physiological monitoring or careful behavioral observation. Reduced responsiveness is a key indicator of sleep, but testing responsiveness can disturb the animal.

Overlooking Eye Closure Variability

Eye closure is not a reliable indicator of sleep across all species. In draughtsboard sharks, eye closure was found to be a poorer indication of sleep than flat body posture and reduced metabolic rate, as reported in Energy conservation characterizes sleep in sharks. Some animals sleep with eyes open, and some close their eyes during quiet wakefulness.

Ignoring Ecological Context

Sleep posture cannot be interpreted without understanding the ecological context. A reptile sleeping in an exposed location is making different tradeoffs than one in a concealed site. Predation pressure, competition, and microclimate all shape sleep characteristics, as emphasized in The ecology of sleep in non-avian reptiles.

Confusing Torpor with Sleep

Torpor and hibernation are distinct from sleep, though they share some features. Torpor involves a controlled reduction in body temperature and metabolic rate that can last for hours or days. Sleep is a reversible behavioral state with specific electrophysiological correlates. The evolutionary model proposes that nocturnal rest evolved into shallow torpor, suggesting a continuum instead of a sharp boundary, as discussed in Evolution of wakefulness, sleep and hibernation: from reptiles to mammals.

Welfare and Safety Context

Sleep posture serves as a welfare indicator for domestic animals. Changes in sleep behavior can signal pain, stress, or disease.

Equine Welfare Assessment

Time budget measures can complement conventional welfare indicators in horses. The study of 174 horses found that time spent standing immobile resting correlated with negative welfare indicators, while time spent feeding, in exploratory walking, and in observation behavior correlated with positive welfare. The study emphasizes the importance of precisely defining and measuring types of attention as a window into an animal's internal state, as reported in Farm Atmosphere: Calm Attention and Mobility Characterise Positive Horse Welfare.

For horse owners and managers, the following assessment steps are recommended:

1. Observe horses during quiet periods when they are calm.
2. Record the proportion of time spent standing immobile versus lying down.
3. Note the posture of recumbent horses, including whether they lie on the sternum or flat on the side.
4. Monitor for changes in sleep posture over time.
5. Escalate to veterinary assessment if a horse shows a sudden increase in standing sleep, reluctance to lie down, or difficulty rising.

Pain Related Sleep Disruption

Pain can disrupt normal sleep postures. Horses with gastric ulceration may show changes in lying behavior, and problem behaviors may persist even after the underlying disease resolves. The behavioral medicine approach to equine gastric ulcer syndrome includes management of underlying diseases, environmental modification, behavior modification, and in select cases behavior-modifying medication, as discussed in Incorporating a Behavioral Medicine Approach in the Multi-Modal Management of Chronic Equine Gastric Ulcer Syndrome.

Safety Considerations for Observers

Observing wild animals requires attention to observer safety. Maintain a safe distance from large mammals, venomous reptiles, and animals with young. Use binoculars or telephoto lenses instead of approaching closely. Never attempt to handle a sleeping wild animal. For domestic animals, be aware that a sleeping animal may startle and react defensively when awakened.

Limitations of Sleep Posture Research

The scientific literature on animal sleep postures has significant limitations that affect interpretation.

Taxonomic Bias

Research on sleep is heavily biased toward mammals and birds. Reptilian sleep remains understudied and without systematic direction, as noted in The ecology of sleep in non-avian reptiles. Sharks received almost no attention until recent studies, and electrophysiological recordings in sharks have proven technically challenging due to signal instability, as documented in An electrophysiological correlate of sleep in a shark.

Methodological Challenges

Identifying sleep in animals that must remain active presents unique challenges. For sharks that swim continuously to breathe, behavioral shutdown and postural relaxation cannot be used as sleep indicators. Electrophysiological recording in these species is complicated by electrode instability and movement artifacts, as reported in An electrophysiological correlate of sleep in a shark.

Inference from Limited Evidence

Many proposed explanations for sleep postures remain hypotheses instead of established findings. The biomechanical hypothesis for bat hanging, the fetal head down hypothesis for primate brain evolution, and the evolutionary model linking reptilian behavior to mammalian sleep states are all working hypotheses that require further testing. The sources for these hypotheses include Why bats hang upside down: a biomechanical hypothesis, Fetal head-down posture may explain the rapid brain evolution in humans and other primates, and Evolution of wakefulness, sleep and hibernation: from reptiles to mammals.

Professional Escalation Criteria

Field observers should escalate concerns to appropriate professionals under specific circumstances.

Veterinary Escalation for Domestic Animals

Contact a veterinarian if any of the following are observed:

1. A horse or cow that does not lie down for more than 24 hours
2. An animal that lies down but cannot rise
3. Sudden changes in sleep posture accompanied by reduced appetite or lethargy
4. Recumbent animals with labored breathing
5. Any animal showing signs of pain when changing position

Wildlife Professional Escalation

Contact wildlife authorities or a wildlife rehabilitator if:

1. A wild animal is observed sleeping in an unusual location, such as on the ground during daylight for a nocturnal species
2. An animal appears unable to maintain a normal sleep posture due to injury
3. Multiple animals in a population show abnormal sleep behavior, which may indicate environmental contamination or disease outbreak

Research Ethics Escalation

Researchers should consult their institutional animal care and use committee before conducting any study that involves disturbing sleeping animals. Physiological recording, such as electroencephalography, requires surgical implantation in many species and must be conducted under approved protocols.

Frequently Asked Questions

What animals sleep standing up?

Horses, cattle, elephants, and some birds can sleep while standing. This posture is made possible by anatomical adaptations that allow joint locking with minimal muscular effort. Standing sleep is typically light sleep that allows rapid arousal. Horses and cattle require periods of recumbent sleep for full restorative rest, particularly for REM sleep. The reticulospinal system plays a role in postural adjustments and sleep atonia, as reviewed in Reticulospinal Systems for Tuning Motor Commands.

What animals sleep upside down?

Bats are the most well known upside down sleepers. The hanging posture allows bats to take flight by releasing their grip and falling into the air, which is energetically efficient. The biomechanical hypothesis for this posture is presented in Why bats hang upside down: a biomechanical hypothesis. Some primates also sleep in upright or head down positions, and the fetal head down posture in anthropoid primates has been proposed as a factor in brain evolution, as discussed in Fetal head-down posture may explain the rapid brain evolution in humans and other primates.

What animals sleep on their back?

Domestic dogs and cats commonly sleep on their backs, exposing their ventral surface. This posture indicates a high level of comfort and perceived safety, as the ventral surface is vulnerable. The posture also serves thermoregulatory functions by allowing heat dissipation. Some primates may also sleep on their backs in safe environments.

How do animals that need to breathe while sleeping manage?

Fur seals and cetaceans use unihemispheric slow wave sleep, where one brain hemisphere sleeps while the other remains awake. This allows the animal to continue swimming, maintain movement for posture stabilization, and surface to breathe. The fur seal can briefly open one eye while having a sleep electroencephalogram in one hemisphere, as documented in Sleep in the northern fur seal.

Do sharks sleep?

Yes, sharks sleep, but the pattern varies by species. Draughtsboard sharks show sleep characterized by lower metabolic rate and flat body posture, with eye closure being a less reliable indicator. Research supporting this is presented in Energy conservation characterizes sleep in sharks. Sharks that must swim continuously to breathe present challenges for sleep identification, and electrophysiological recording in these species remains technically difficult, as discussed in An electrophysiological correlate of sleep in a shark.

How does sleep posture relate to evolution?

Sleep posture reflects evolutionary pressures including predation risk, thermoregulation, and respiratory demands. One model proposes that reptilian waking gave origin to mammalian sleep, with specific reptilian behaviors evolving into NREM and REM sleep states, as presented in [Evolution of wakefulness, sleep and hibernation: from reptiles to mammals

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References and Further Reading

• NCBI Literature Resources. National Center for Biotechnology Information.
• PubMed. National Library of Medicine.
• Sleep in the northern fur seal.. Current opinion in neurobiology, 2017.
• The ecology of sleep in non-avian reptiles.. Biological reviews of the Cambridge Philosophical Society, 2022.
• Reticulospinal Systems for Tuning Motor Commands.. Frontiers in neural circuits, 2018.
• Evolution of wakefulness, sleep and hibernation: from reptiles to mammals.. Neuroscience and biobehavioral reviews, 2010.
• Energy conservation characterizes sleep in sharks.. Biology letters, 2022.
• Fetal head-down posture may explain the rapid brain evolution in humans and other primates: An interpretative review.. Brain research, 2023.
• An electrophysiological correlate of sleep in a shark.. Journal of experimental zoology. Part A, Ecological and integrative physiology, 2024.
• A journey within: Reflections on sleep apnea, evolution, and the mind-body axis in sleep medicine.. Explore (New York, N.Y.), 2025.
• Farm Atmosphere: Calm Attention and Mobility Characterise Positive Horse Welfare.. 2026.
• Incorporating a Behavioral Medicine Approach in the Multi-Modal Management of Chronic Equine Gastric Ulcer Syndrome (EGUS): A Clinical Commentary.. 2025.
• An overview of the benefits of animal-assisted interventions in medical and therapeutic contexts for human health: cognitive mechanisms, sensory perception and welfare considerations.. 2026.
• On Churchill's black dog, Barzun's bicycle, and cartoon bears: living within the bipolar temperament.. 2026.
• Bat Loves the Night. 2001.
• Why bats hang upside down: a biomechanical hypothesis.. Journal of Theoretical Biology, 1977.
• Evolutionary aspects of sleep and stress interaction: phylo-, ontogenetic approach. Zhurnal Evoliutsionno Biokhimii I Fiziologii, 2009.

This article is educational and does not replace institutional policy, professional advice, or applicable safety and regulatory requirements.