Like the shoulder blade, the humerus is also extremely expanded for massive muscles to attach. Instead of moving back and forth like our arms, it can rotate. The way the humerus (the long bone in the upper arm) moves is also different in platypuses and echidnas than in other mammals. Again, it is more like a lizard shoulder than a mammal. If you ever see big plates of bone in a skeleton, that normally means that there are large muscles attached, and the platypus’ massive scapula is the attachment-site for large forelimb muscles that allow them to dig their burrows. The scapula (shoulder blade) is HUGE – as big as in any mammal I can think of (relative to body size). Platypus and echidna shoulder girdles are also unlike any other living mammal – they have bones and articulations that do not exist elsewhere in the mammalian class. The large scapula and humerus allow for massive digging muscles. Platypus limbs are held sideways out from their bodies, like a lizard. On the whole, platypuses are so well adapted that their skeletons have remained relatively unchanged since non-avian dinosaurs were around. By contrast all other mammals have straightened limbs which sit below their bodies. This is one of the features that the earliest mammals inherited from the reptilian ancestors they evolved from, and something that has never changed in the evolution of the platypus. One of the very many ways that platypus (and echidna) skeletons differ from every other living mammal is that they have bent elbows and knees, with their legs held out sideways from their bodies much like a lizard. Aside from their relatives the echidnas, and one species of dolphin, platypuses are the only mammals known to detect electricity.Īdult platypuses have no teeth (juveniles have five to six ( one is displayed in our Micrarium) but they are resorbed by the time they leave their burrows) – instead they mash their food up with horny pads inside the bill. This contains highly specialised receptors that can detect the miniscule electric impulses that are generated by the muscular contractions of their underwater invertebrate prey. These bony prongs are the scaffold which supports their extraordinary leathery bill. Females nurse their young for three to four months until the babies can swim on their own.The front of a platypus’ skull resembles the pincers of an earwig. The eggs hatch in about ten days, but platypus infants are the size of lima beans and totally helpless. A mother typically produces one or two eggs and keeps them warm by holding them between her body and her tail. It is one of only two mammals (the echidna is the other) that lay eggs.įemales seal themselves inside one of the burrow's chambers to lay their eggs. Platypuses use their nails and feet to construct dirt burrows at the water's edge. However, the webbing on their feet retracts to expose individual nails and allow the creatures to run. On land, platypuses move a bit more awkwardly. Platypuses do not have teeth, so the bits of gravel help them to “chew” their meal. All this material is stored in cheek pouches and, at the surface, mashed for consumption. They scoop up insects and larvae, shellfish, and worms in their bill along with bits of gravel and mud from the bottom. These Australian mammals are bottom feeders. ![]() In this posture, a platypus can remain submerged for a minute or two and employ its sensitive bill to find food. ![]() Folds of skin cover their eyes and ears to prevent water from entering, and the nostrils close with a watertight seal. Platypuses hunt underwater, where they swim gracefully by paddling with their front webbed feet and steering with their hind feet and beaverlike tail. They have sharp stingers on the heels of their rear feet and can use them to deliver a strong toxic blow to any foe. The animal is best described as a hodgepodge of more familiar species: the duck (bill and webbed feet), beaver (tail), and otter (body and fur). In fact, the first scientists to examine a specimen believed they were the victims of a hoax. The platypus is among nature's most unlikely animals.
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