The Strange Animal Called a Platypus
This Unique Species is Part Mammal, Part Reptile
by Lucy Ji, age 13
Looking something like an unusual cross between a duck and a beaver, the platypus has a bizarre appearance.
At about 20 inches long, the platypus has a glossy, sleek, brown coat and an ivory-colored underside. The most distinctive features of the platypus are its rubbery bill and its leather-like webbed feet. Protruding from each individual toe is a long, sharp claw. A beaver-like tail not only helps propel and steer the platypus as it swims, but also serves as a fat reserve, storing energy during hard winter months.
The platypus is classified as a semi-aquatic animal, meaning it spends time on land as well as in water. Several adaptations help it survive in its natural environment. One example is its nostrils, which are located on the bill. When the platypus swims, the nostrils close to prevent water from coming in. Once it leaves the water, the nostrils open again.
A typical diet for the platypus consists of fish, worms, insects, fish eggs, frog eggs, tadpoles, and shrimp. It will also eat small fish and frogs. The platypus uses its bill to poke about in the underwater soil for food and to push around and dig in the mud for insect larvae.
Another unusual fact about the platypus is that it has a reptilian gait. This means its legs protrude from the sides of the body and not from beneath its body.
On top of all of its other unique physical characteristics, the platypus is a monotreme. Monotremes are mammals that lay eggs. For an animal to be a true mammal, the mother must give birth to live offspring and feed them with her own milk.
In other words, a monotreme integrates the characteristics of a reptile and a mammal. A female platypus lays eggs like a reptile does, but when the young eggs hatch, the mother feeds them with milk from her skin pores. This makes the platypus only a partial mammal and therefore, a monotreme.
The average body temperature for the platypus is only 90 degrees Fahrenheit compared to the typical 99 degree Fahrenheit for mammals. Scientists believe this temperature difference is due to a special adaptation to severe weather and environmental conditions.
The platypus is armed with sharp claws and deadly venom. Many people assume that the platypus is just a small harmless creature that dwells in swamps and forests. The venom, which is mainly used for defense, comes from a spur on the hind limb. Although it is powerful enough to kill small animals, this venom can only cause humans “excruciating” pain, as described by Dr. Stephen Maturin, an eager researcher who was stung by the animal he admired so much.
The venom instantly spreads throughout the poisoned limb, bringing incapacitating pain, which then develops into hyperalgesia, a heightened sensitivity to pain which can last for days, or even months.
After careful experimentation and high-tech liquid chromatography, scientists found that the venom caused the affected nerve cells to take up calcium ions. This is probably why the venom causes so much pain; the heightened calcium levels in the nerve cells are linked to the sensation of pain.
Later, scientists Masaki Kita and Daisuke Uemura of Japan isolated venom called heptapeptide-1, which causes the calcium ion level to increase. This finding suggests that this peptide is responsible for the venom’s painful effect. Because only males can produce venom, statistics show that venom production increases during breeding season in order to fight other males who are also competing for mates.
The seemingly harmless platypus happens to have a couple of tricks up its sleeve. If you are ever visiting Australia and happen to see one, be curious, but also careful.
[Sources: New York Times; www.wikpedia.org]