The Echidna (Tachyglossus aculeatus) – A Weird and Wonderful Animal

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Echidnas are Monotremes, a type of animal that has been on earth since the time of the dinosaurs.

Echidna
photo courtesy of Dr. Lloyd Glenn Ingles, California Academy of Sciences.

The oldest known monotreme fossils are over 120 million years old, making this the oldest type of mammal on earth. There are only three species of animal in the Order Monotremata: the long-beaked echidna, the short-beaked echidna, and the platypus. Echidnas are found in Australia and Papua New Guinea, and are about the size of a football.

There are lots of weird things about echidnas, in addition to their spines (and no, they aren’t related to hedgehogs or porcupines):

  • They have no teeth.
  • They have long beaks.
  • The opening for their mouth is only 1/4 inch wide, and the jaws do not move up and down.
  • Their rear feet point backwards.
  • Like birds, they only have one orifice for urination, defecation, and reproduction.
  • And they lay eggs!

European scientists had been studying the echidna for more than ninety years before they discovered that this small mammal lays eggs. In 1884 Dr. William Haacke unrolled a captive echidna in hopes of finding a “puggle,” (a baby echidna) in her pouch. Instead, he found an egg, and was so excited about his discovery that he accidental broke it!

The eggs are about the size of a dime, but the puggles are so small when they hatch that they weigh only about 1/7th as much as a dime. The egg is deposited by the mother into a pouch on her belly 22 to 24 days after mating, and it will hatch 10 1/2 days later. The puggle is not fully formed when it breaks out of the egg, but is capable of crawling from the pouch to an area on it’s mother where it can suckle milk that oozes from specialized glands. When the puggle hatches, it’s hind legs are only bumps, and it’s eyes are dark spots beneath it’s transparent skin.

The puggle will grow quickly as it lives in it’s mother’s pouch, and it’s hind legs and feet take on recognizable shapes a few days after hatching, When it is between 30 and 40 days old, it starts to be covered with fuzz, and soon the hair and spines start to grow.

By this time the puggle is so big the mother will have trouble moving with the baby clinging to her belly as she walks. Soon, 50 to 60 days after it’s birth, the puggle will be left in a burrow that the mother digs underground, and it will stay there alone until it’s about 7 months old. The mother will come once every four to five days to nurse, and the baby will drink as much as 40% of it’s body weight at each feeding! (Just for fun, figure out how many pounds you would have to eat at one meal to equal 40% of your own body weight. It’s a pretty big pot of soup, isn’t it?)

At seven months, the mother brings the baby to the mouth of the burrow, feeds it one more time, and walks away. The young echidna is now entirely on it’s own.

Echidnas eat grubs, termites and other small insects, which are caught on the long sticky tongue and sucked into the tiny mouth on the bottom of it’s beak. There are no teeth, and the jaws do not move up and down like most mammals. Instead of teeth there is a ridged area on the palate that looks a lot like a kitchen grater, and a rough place at the back of the tongue. The food is ground between these specialized areas before swallowing. In order to find their food, the echidna has very powerful hearing, and they dig with their extremely strong front and hind legs. If the insect or grub is too big to fit into their tiny mouths, the echidnas break the food into smaller pieces with the end of their beaks. An echidna that has been injured on its beak by a car or other accident will not survive, because it won’t be able to eat.

Echidnas are a protected species in Australia, but they are so secretive that no one knows how many there are. There have been no successful breeding programs to date in any of the many zoos where captured echidnas have been kept. Echidnas in the wild are not social animals. Each individual lives alone in an area large enough to support it, and the babies leave their mother’s territory in order to find an unoccupied place of their own. This also makes it difficult for scientists to count them.

Scientists have found that these “primitive” animals are quite intelligent, with large brains and a learning capacity that is equal to a rat or cat. Captured echidnas can be easily taught to respond to a signal (as long as they know it means “dinner”!) and wild echidnas that have been fitted with radio transmitters by scientists quickly learn the frequency of their own radios and use the sound to know that a scientist is near and trying to find them. (Just for fun, imagine how our lives would be different if we had evolved from egg laying monotremes instead of primates. It would make a very interesting short story, wouldn’t it?)

I learned this information about echidnas from the wonderful book by Dr. Peggy Rismiller called The Echidna: Australia’s Enigma . For more information on this fascinating animal, and the lives of the scientists who study them, look for this book at your local library.

Be sure to visit edgeofexistence.org, where you’ll learn about extraordinary mammals that are close to extinction – including the long-beaked echidna from New Guinea and the short-beaked echidna from Australia.