X- ray of Gila monster, white dots represent osteoderms Hello, I am a real monster - skull with front limbs Heloderma change their teeth all their lives long (Ref. If a tooth brakes off by accident, it has to wait until its "wave" is to start again. The next "wave" replaces teeth No 2, 5 and 8, etc. The exchange of teeth follows a wave – like pattern: at about the same time tooth No 1, 4 and 7 are replaced. The base of the new tooth is covered by new material from the jaw. When a tooth is replaced, its base is absorbed and the fully developed reserve tooth is brought into position from the inside of the jaw (lingual) (Ref. The base of a tooth is flattened, irregularly grooved and tightly embedded into the beveled jaw (pleurodont).It is not possible to distinguish between incisors and molars (Ref. 1)Įvery tooth is sharply tipped and has an apparent longitudinal groove to apply venom to a victim. The venom is used for protection but not to immobilize prey. If you smell it you can be sure the monster is irritated and ready to bite. Via individual venom ducts of the lobes the venom is transported through the gums into the grooves of the teeth (Ref. Replacement teeth at different age of developmentĪt both sides of the lower jaw venom glands with 3 to 4 lobes are located. Heloderma skull with lower jaws (mandibles) Large, unexpected objects in motion are recognized and answered by a hissing sound. It has a transparent nictitating membrane (third eyelid), which can be pushed over the cornea from the nose-side angle for protection and moistening (Ref. The eye has a roundish pupil and two moveable eye lids. In doing so their pulse is accelerated at the side of the neck with eyes wide open. Soft noises at a distance of three feet are perceived and lead them to wake up. The ear has a strong tympanum, which is visible from the outside. The JACOBSON-organ functions similar to the nose of mammals. This information is transferred to the brain to be "decoded". The JACOBSON-organ analyzes smell particles which are brought via the tips of the tongue. The roof of the mouth embeds the JACOBSON-organ within small grooves. The tongue serves, e.g., for food transport into the throat, drinking, swallowing, licking the content of eggs and for cleaning the outside mouth (Ref. It is fixed to the hyoid bone and is extremely flexible. The tongue of the Heloderma is forked at its tip and is dark in color. It only opens while breathing in or out (Ref. The glottis ends at about the middle of the lower part of the mouth and seals the end of the trachea. The trachea supplies the lungs with air and oxygen.
Adult lizards are capable to swallow medium sized rats, one day old chickens or juvenile rabbits. The throat of Heloderma is quite extendable. Heloderma can easily smash the head of small rodents (pers. The bite and holding of the victim is supported by the very strong adductor- muscle at the end of the jaws. The osteoderms ("Skin bones") in the head region are connected to bones of the skull (Ref. depressor mandibularis (opening of jaws), 3) M. * 1) Musculus adductor (closing of jaws), 2) M. Schematics of the main muscles of the skull of H.susp.*Įxposed venom glands: 1) venom glands, 2) trachea Heloderma from the southern range of distribution are naturally smaller and apparently tend to have less weight.Įxternal ear with tympanic membrane of H.Susp.
After a meal, it is significantly larger in diameter for a few days. The tail represents one of the fat reservoirs. In the wild, individuals are significantly lower in weight, because they have less of a chance to deposit abundant fat reservoirs. Adult individuals in captivity with regular feeding can attain a weight of about 1200 g. The Gila-Monster from the northern range of distribution will reach a total length of about 50 cm.