The human-animal bond is a mutually beneficial and dynamic relationship between people and animals that is influenced by behaviors essential to the health and wellbeing of both.
This includes, among other things, emotional, psychological, and physical interactions of people, animals, and the environment.
The idea of bonding with animals such as reptiles seem creepy, or even impossible, yet some people insist that their reptiles know them and enjoy being with them. Can reptiles feel or portray emotions?
The cerebrum is the most highly developed part of the brain and is responsible for thinking, perceiving, producing and understanding language.
Most information processing occurs in the cerebral cortex.
The cerebral cortex is divided into four lobes that each have a specific function. These lobes include the frontal lobes, parietal lobes, temporal lobes, and occipital lobes.
Although pallial structures exist in amphibians and fish, reptiles and mammals are the only vertebrates to possess a cerebral cortex with a clear, though simple, a three-layered structure similar to that of mammalian allocortex.
The reptilian ventral pallium also gives rise to the dorsal ventricular ridge (DVR), a structure that dominates the bird pallium and contributes to the complex cognitive abilities of birds, but whose mammalian equivalent is still the subject of debate among comparative anatomists.
The cerebral cortex is involved in several functions of the body including:
- Determining intelligence
- Determining personality
- Motor function
- Planning and organization
- Touch sensation
- Processing sensory information
- Language processing
It is true that reptiles display a diversity of behavior that is reflective of their evolutionary heritage from fish and amphibians and their ancestral contribution to the diversity found in birds and mammals.
Much of the behavior observed in reptiles seems specific to the ecological setting within which they live. As a result, a diversity of behavior is found in each of the groups of modern reptiles.
Recent studies on the social behavior of lizards have proved them capable of a variety of behavioral postures, sequences, and sociality that exceeds that found in some mammals and birds.
While many species of lizards are territorial, others are hierarchical and some have harems.
For all those territorial species studied, crowding results in increased social interaction, increased aggression, and a switch to hierarchical behavior.
While smell and sound may be important stimuli for social behavior in some reptiles, posture, actions, and especially color appear to be most important in diurnal lizards.
Recent studies with temperature and energy suggest that the large extinct dinosaurs probably fought considerably less than commonly portrayed in movies and stories.
Fear and aggression are the two main emotions, but they may also demonstrate pleasure when stroked or when offered food.
According to Dr. Sharman Hoppes, clinical assistant professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences agrees that generally, reptiles demonstrate basic emotions.
“A snake that is feeling aggressive may warn you with a hiss,” states Dr. Hoppes. “This can occur when you are forcing your attention on the snake, and if you persist, they may strike out. Typically snakes hiss or coil when they are feeling hostile, but most pet snakes are not aggressive animals unless threatened.”
A reptile that is feeling fear may simply try to get away, but it can also exhibit actions similar to aggression.
For this reason, it is a good idea to keep handling sessions with a new reptile to a minimum until it gets used to you.
Otherwise, you may scare it into striking at you, a perceived threat. It is better to have a good session without upsetting the animal that lasts two minutes than a longer session trying to force a reptile to accept you.
A more controversial emotion in reptiles is the concept of pleasure or even love. Many feel that they have not developed this emotion, as it does not naturally benefit them.
However, most reptiles do seem to recognize people who frequently handle and feed them.
“I don’t know if it is love,” says Dr. Hoppes, “but lizards and tortoises appear to like some people more than others. They also seem to show the most emotions, as many lizards do appear to show pleasure when being stroked.”
Some species of mud turtles protect their egg nests through the incubation period. Much as, female alligators also stay with their young and will guard them for up to six months, teaching them survival skills and vocalizing with them through a series of grunts.
Whether this is due to a survival instinct or concern for their individual offspring is unknown to science.
When it comes to interactions with humans, some reptiles do seem to enjoy company. A tortoise that enjoys being petted might stick its neck out or close it eyes and become still and calm during the interaction. The same is true of lizards.
“Some reptiles do appear to enjoy human contact,” adds Dr. Hoppes, “especially when food is offered. Many will respond to feeding times, coming to certain people they associate with food. And certainly, most iguanas prefer certain people over others.”
Iguanas have individual personalities that can vary from tranquil and laid-back to aggressive and dominating.
The latter can be very difficult to live with and care for. The more calm iguanas, however, tend to bond with their person but may only endure handling by that individual. It is the rare iguana who is social with strangers.
Numerous reptile owners believe that their personal reptiles do recognize the good intentions they have towards them. Others deem that their cold-blooded dependents only tolerate them when they have to and would prefer to be left alone.
By careful observation and handling of your reptiles, you can determine which are more social and which may not be quite so impressed with having a human as a best friend.
Almost all of the studies on amphibian and reptilian behavior have been in the evolutionary context of the behavior as a premating species isolating mechanism. Thus, the majority of amphibian studies have been on the mating calls of frogs and toads or on the complicated courtship patterns of salamanders. Almost all of the studies on amphibian and reptilian behavior have been in the evolutionary context of the behavior as a premating species isolating mechanism.
Thus, the majority of amphibian studies have been on the mating calls of frogs and toads or on the complicated courtship patterns of salamanders.
Reptilian studies have been primarily with diurnal lizards (iguanids, agamids, varanids) and have described species differences in courtship or aggressive displays.
The evolution of chemical signaling in reptiles, along with behaviors governed by pheromones including conspecific trailing, male-male agonistic interactions, sex recognition, and sex pheromones, and reptilian predator recognition.
In addition, these natural and sexual selection processes which have lead to complex chemical signals whose different components and concentrations provide essential information about individuals to conspecifics.
Is the reptilian brain really just a mammalian brain missing most of the parts? Some 320 million years ago, the evolution of a protective membrane surrounding the embryo, the amnion, enabled vertebrates to develop outside of water and thus to invade new terrestrial niches.
These amniotes were the ancestors of today’s mammals and sauropsids (reptiles and birds). Present-day reptiles are a diverse group of more than 10,000 species that comprise sphenodons (‘Tuatara’), lizards, snakes, turtles, and crocodilians.
Although turtles were once thought to be the most ‘primitive’ among reptiles, current genomic data point toward two major groupings: the Squamata (lizards and snakes); and a group comprising both the turtles and the Archosauria (dinosaurs, modern birds and crocodilians).
Although pallial structures exist in amphibians and fish, reptiles and mammals are the only vertebrates to have a cerebral cortex with a clear, though simple, three-layered structure, similar to that of mammalian allocortex.
The reptilian ventral pallium also gives rise to the dorsal ventricular ridge, a structure that dominates the bird pallium and contributes to the complex cognitive abilities of birds.
The reptilian cortex contains far fewer subdivisions than that of rodents, carnivores, or primates: it is subdivided into a medial cortex, often called hippocampus by anatomists; a lateral cortex, equivalent to the mammalian piriform cortex; and a dorsal cortex in between, which receives multimodal inputs (for example, visual inputs in turtles).
There is little evidence for motor and somatosensory areas in the reptilian cortex, but pallial motor control may have evolved early in vertebrate evolution. Owing to this simplicity, the reptilian brain facilitates the study of primordial cortical function as a whole and points to the origins of cortex as fulfilling general associative functions.
Challenging this view, however, recent molecular studies have found that turtle and lizard cortical neuroblasts generate neurons that express upper layer molecular markers, in a developmental sequence similar to that observed in mammals.
Although the molecular characterization of neuronal types in the reptilian cortex is still in its infancy, it is possible that the reptilian cortex represents an ancestral blueprint for the more elaborate mammalian cortical circuits. For example, reptilian cortical neurons, or subsets of them, might share molecular (and functional) features with both upper and lower layer mammalian cells.
Cortical circuitry is where most of the comparative work on the reptilian brain has been done. In the three-layered reptilian cortex, afferent inputs travel medially through superficial L1, where they fan out in a non-topographic manner.
In turtles, visual stimulation triggers propagating waves of neural activity that travel across the cortex. These waves are slower and simpler than those observed in mammalian neocortex.
Modern reptilian cortex resembles that in the common ancestor of reptiles and mammals, understanding reptilian cortex function may reveal some of the fundamental associative computations that early cortical circuits evolved to carry out.
Reptiles are ectotherms and must behaviorally or physiologically adapt to varying temperatures, making reptile brains notable for their adaptation to extreme conditions.
The turtle brain, for example, has evolved remarkable adaptations to hypoxic conditions, which have long been known to experimentalists interested in hearing, olfaction, motor control or cerebellar physiology.
