BEARDED DRAGON BEHAVIORS
Compared with many lizards, inland bearded dragons display a wide range of social behaviors. For obvious reasons, they will only display the full range of these behaviors once they reach sexual maturity and if they are kept in a group. Following are some of the behaviors you will notice in this species.
In the wild or in captivity, bearded dragons raised in a group form social hierarchies relatively early in life. Using the terminology of animal behavior, the leader of any group is called the alpha animal.
If you raise a group of baby bearded dragons it quickly becomes apparent that some individuals are “top dogs,” while others are submissive. During the immature stages, a clear distinction is usually seen between several of the more dominant individuals (rather than one alpha animal) and the more submissive dragons. The dominant dragons are more vigorous in their feeding behaviors and intimidate smaller, more submissive animals. As a pattern, bearded dragons that are aggressive feeders grow faster, which makes them need to eat more, which makes them more aggressive feeders, grabbing increasing portions of the food offered. Over time, intimidated smaller animals wisely become wary of the quick and daring feeding behaviors of larger ones, and thus have less access to food. They end up eating less and remaining smaller unless moved to separate rearing containers. Dominant juvenile bearded dragons, if hungry and underfed, often turn to mutilating the tail tips, digits, and even lower limbs of less dominant animals. Larger immature bearded dragons may also attempt to eat smaller ones. In the world of bearded dragons, the first months of life are a ruthless race to feed and reach large size.
Damaged limbs from intraspecies mutilation in subadult bearded dragons do not grow back, and injured animals are permanently handicapped.
Once bearded dragons mature, their new reproduction-related behaviors kick in. Social hierarchies become more defined with a large male becoming the alpha animal of the group.
Climbing and Basking Site Hierarchies
Inland bearded dragons are considered semi-arboreal animals and will readily climb shrubs, rock piles, and fallen tree trunks when available. These raised structures often form the topographical nucleus of a group of bearded dragons.
In the wild and in well-designed greenhouse enclosures, bearded dragons compete for prime basking areas, usually the highest and most easily accessible sites such as fence posts, fallen trees, shrubs (such as the tops of large jade plants), or rock outcrops. Typically, the alpha male of a group acquires the top position on a basking site.
The baby bearded dragon basking under a spotlight is gaping to dissipate heat.
Like most reptiles, bearded dragons can raise their body temperature relatively quickly, but they cool down slowly, and cannot readily cool below air temperature. The preferred daytime body temperature of bearded dragons is around 98° F, which they can easily achieve by basking in sunlight even at air temperatures 10 or more degrees cooler than the target body temperature.
Bearded Dragons flatten and darken their bodies to increase heat absorption and quickly raise body temperature when exposed to sunlight. Bearded dragons can also warm their bodies by absorbing radiant heat from warm surfaces such as rocks or the ground. In the wild, as midday air temperatures rise toward 103° F, bearded dragons usually remain hidden and sheltered from the sun because they have a limited ability to cool below air temperature. That is the reason it is very important that a basking site in a vivarium be offset by a cooler section. We have had several reports of bearded dragons that are heated day and night with one or more spotlights and heat strips running the length of a vivarium gaping for extended periods of time, that are hyperactive and obviously heat stressed, who suddenly die. The importance of a cooler sheltered area in the upper 70s to low 80s during the day cannot be emphasized enough.
Gaping or Panting When Basking
Some bearded dragons choose to remain at high temperatures and may gape (keep the mouth open) or pant (keep the mouth open while performing throat movements to increase the rate of air flow in and out of the mouth and lungs) while basking. Gaping is also performed in the initial stages of overheating, presumably in an attempt to cool down. This behavior should not be of concern to owners unless their vivarium is overheated and fails to provide cool areas. If the enclosure is too hot, heat sources should be turned off and the vivarium design adjusted to provide a heat gradient. Gaping and forced exhalation may also occur in bearded dragons with respiratory infections, with lung damage from inhaling too much dust, or with certain types of parasite infection. Clearly, interpreting the cause of gaping must be made in the context of husbandry, often with a veterinarian’s help.
This eastern bearded dragon is extending its beard. Photo by David Travis.
Open-Mouth Bearded Display
Bearded dragon hatchlings perform the classic display of an open mouth with beard extended toward large moving objects they interpret as threats. It’s easy to see how this defensive display earned these lizards their common name. In captivity, most bearded dragons readily habituate to movements by their caretakers and the propensity to perform the open-mouth display quickly wanes. Nonetheless, the potential to perform this display remains throughout the life of a bearded dragon. The eastern bearded dragon tends to perform this display much more readily than inland bearded dragons and is not as likely to habituate to large moving objects. However, any suddenly startled individual may perform a bearded display (left), and individuals who are considered aggressive do so even more readily. Higher temperatures in the 90s will usually increase the likelihood of a bearded dragon performing a bearded display. No matter how habituated a bearded dragon may become to humans, suddenly exposing bearded dragons to certain animals such as snakes and monitors seems to readily elicit the display and is a trick resorted to by herp photographers.
Juveniles of all the popular species may mutilate cage mates. This behavior is most readily performed by stage 2 animals, usually by larger individuals toward more passive ones when not enough food is available. Tail tips, toes, and sections of limbs may be bitten off by hungry and more assertive individuals. In extreme cases, when a smaller dragon is of gobbling size, larger, more dominant juveniles may attempt cannibalism.
Until recently, we had not witnessed mutilation in subadult or adult bearded dragons. Specific conditions, however, did result in a significant level of mutilation incidence (eight subadults and two young adults were mutilated within a week) in a large breeding facility. Three factors were identified as contributing to mutilation: limited food availability, overcrowdedness, and high temperatures (90–105°F). Large adults seldom mutilate other dragons of similar size. Close observation of bearded dragons usually reveals that when mutilation does occur in subadults, it is often one individual doing the damage in a group. Within a group, if the conditions leading to mutilation persist, the end result is often a single able and actively feeding individual and several feeding handicapped and crippled dragons.
This adult female bearded dragon lost a hind limb when young.
Arm-waving is the earliest social behavior in bearded dragons and it can be witnessed within days of hatching. It serves both as an intraspecies signal (basically, “I’m a bearded dragon.”) and as an appeasement gesture (“Please don’t hurt me.”). It persists as an appeasement/submissive gesture in adult females during breeding. More rarely it is performed by submissive males when more aggressive males bite their necks.
Bearded dragons commonly adopt a position in which most of the tail is curled up above the ground as they remain still. This is a sign of being on alert and is commonly performed by adult bearded dragons throughout the day.
This female eastern bearded dragon is arm-waving.
Head-Bobbing or Head-Jerking
Head-bobbing refers to a lowering and quick raising of the dragon’s head, usually performed in repetitive sets. The lifting component of the behavior can be so vigorous that the entire front of the body jerks upward. This behavior (called head-jerking by some) is most often seen when males are in breeding/territorial mode, usually exhibiting a black beard. This is a sexual display performed as a part of courtship toward females prior to copulation.
At the onset of the breeding season, male-to-male encounters and occasional male-male fights occur. These fights are mostly ritualistic and no serious harm comes of them. Typically two males in breeding condition will blacken their beards and perform head-bobbing behaviors. This will be followed by a great bluff performance in which males tilt their flattened bodies toward each other. One of the males may twitch its tail. A male may then try to bite the tail of the other. They may bob and again display flattened bodies to each other. A male may then decide to latch on to the thick ridge of scales around the neck in a movement that resembles breeding, pressing its body on top of the submissive animal. The beaten male flattens on the ground. These behaviors help select for fitness in bearded dragons, allowing the largest, strongest, healthiest, and most spirited males first access to available females.
Tail curling, a sign of alertness, is readily observed in bearded dragons kept in groups. Photo by David Travis.
Dragons taste new foods, new objects, and other dragons with their tongues. Tongue-tasting serves a chemoreceptive function and allows evaluation and identification of food, objects, or other lizards. Tongue-tasting may also be performed by alpha males upon other males prior to performing the head-bobbing display.