Start a Love Train

By CodingStrategies on December 15th, 2017

Pop Quiz: What mammal is covered with spikes, lays eggs, has a four-headed penis, and no nipples? The answer is the echidna, one of the strangest animals that exist on Earth today. Echidnas are the epitome of mammalian weirdness - they have a hodge-podge of reptilian and mammalian features, which was recognized early on by biologists. In 1802, British surgeon and anatomist Everard Home named the curious animal after the Greek goddess Ekhidna (meaning "she viper") who was half-snake and half-woman. She is also called the "Mother of Monsters" because most of the beasties in Greek mythology were reportedly her offspring.

Greek deity Ekhidna lived alone in a cave, was the mate of Typhon, was a flesh-eating horror and had snakes for hair.  Depending on the reference, she may count among her fierce offspring Orthrus (the two-headed dog who guarded the Cattle of Geryon), Cerberus (the three-headed dog who guarded the gates of Hades), the Lernaean Hydra (many-headed serpent who grew extra heads when one was cut off), Ladon (also called Python, the snake that guarded the golden apples in the Garden of the Hesperides), Chimera (a fire-breathing beast that was part lion, part goat and had a snake-headed tail), the Sphinx (riddling monster with the head of a woman and the body of a winged lion), the Colchian Dragon (guarded the Golden Fleece), the Nemean Lion (killed by Hercules as his first labor), the Caucasian Eagle (ate the liver of Prometheus), the Crommyonian Sow (killed by the hero Theseus) and Gorgon (mother of Medusa).

Modern day echidnas are one of only two members of the monotreme family. There are only two monotremes: the amphibious platypus and the terrestrial echidna, native to Australia, Tasmania and New Guinea. Monotremes are mammals that lay eggs, and are considered to be the most ancient living order of mammals. In addition to egg-laying, members share primitive skeletal features such as the shoulder girdle and skull characteristics that have been lost in other living mammals.

Echidnas are also called spiny anteaters, and are usually between 12 and 17 inches long and weigh between 4 and 10 pounds. They have a tiny face, small eyes and a long nose that is also called a beak. The short-beaked echidna has dark fur almost completely hidden by a covering of hollow, barbless quills (modified hairs called “spines”) on its back and sides. Long-beaked echidnas have little fur and more visible spines. The beige-and-black spines on all species, which are about 2 inches long, help camouflage the echidna in the brush. If they feel threatened or they are disturbed, they will use their strong claws to dig into the ground leaving only their spines exposed. If the ground is too hard for digging, they curl into a ball of spines. Like anteaters, the echidna has no teeth; instead, it has a long, sticky tongue to catch and chew the ants, termites, grubs, insect larva and earthworms it eats.

It is a solitary creature and minds its own business, except during mating season. During July and August when a young echidna’s fancy turns to love, they join together in a Love Train. Males line up nose to tail behind a single female, forming a procession of up to a dozen individuals.  Trains can last more than a month, with males dropping out and rejoining, literally chasing the dream of mating with an eligible female. When the female is finally ready to mate, the males dig a trench in the ground around her. The males then compete for mating honors by pushing each other out of the trench. The last one remaining gets to mate first with the female, followed by one or more of the other Love Train passengers.

Mating with multiple males puts a tremendous competitive pressure on the sperms to fertilize the egg. So echidna sperms do something very unusual: hundreds of individual sperms form teams of giant super-sperm bundles. These sperm clusters can swim much faster than individual sperms, and therefore present an evolutionary advantage (no need for ICD-10-CM code Z31.41, Encounter for fertility testing). In addition, males sometimes wake up from hibernation early and sneak into the burrows of still-hibernating females, where they mate with the sleeping lassie. This can result in female echidnas waking up from hibernation and finding themselves pregnant (code Z33.1, Pregnant state, incidental).

An adult female echidna usually lays a single, leathery egg once a year. She rolls the newly laid egg, about the size of a grape, into a deep pouch on her belly to keep it safe. Ten days later, the baby echidna, smaller than a jelly bean and called a puggle, hatches (code Z76.2, Encounter for health supervision and care of other healthy infant and child). The puggle uses its tiny, see-through claws to grip the special hairs within the mother’s pouch. The mother does not have nipples the way other mammals do. Instead, the little puggle laps up milk that the mother’s body secretes from special glands in her pouch (code Z39.1, Encounter for care and examination of lactating mother).  After two to three months, the puggle leaves the pouch, but continues to suckle until completely weaned at about six months.

The echidna has spines like a porcupine, a beak like a bird, a pouch like a kangaroo, and lays eggs like a reptile. They have the lowest body temperature of any mammal (R68.0, Hypothermia, not associated with low environmental temperature), which fluctuates over the course of a day. Their long life spans — up to 50 years in captivity, with anecdotal reports of wild animals reaching 45 years — are due to their low body temperature and slow metabolism. Last, echidnas host the world’s largest flea. Sometimes the world can be a strange and unfriendly place; at least the echidnas are out there pursuing each other for love.