Echidna
fossils indicate that this animal was around 120 million years ago.
This is a long time. Tyrannosaurus Rex fossils indicate that this
animal originated about 68 million years ago. That is, the Echidna
developed about 52 million years before the Tyrannosaurus. The Echidna
then survived whatever killed the dinosaurs and has lived another 65 million years since.
This
does not imply that the Echidna has necessarily not evolved in this
time, but suggests that it has been a successful basic shape through
vastly changing conditions. Echidnas live up to 45 years. They can
breed at about 6 years old. Studies on Kangaroo Island suggest that
they only breed every three to seven years, so the Echidna is not a
prolific breeder.
Breeding
The shape of the Echidna makes the usual mammal mating position impossible. The female
lays down a scent trail and each male that finds it follows the female.
There can be as many as ten males following the female. When she is
finally ready to mate, she digs the front part of her body into the
ground. All the males try to dig under her. If there is more than one
male this results in a doe nut shaped hole. The males try to push each
other out of the hole, pushing nose to nose. When only one is left, he
will have dug slightly under the female and he turns on his side and
puts his cloaca into contact with the female's cloaca. The male can
then extend his four headed penis and complete the mating. The mating
is not completely face to face, but is more like this position than the
usual mammal mating position.
If only one male is present, the hole for mating will be a straight trench.
The
female lays her egg about 22 weeks after mating. It is not known
definitely how the female gets the egg into its pouch, but it seems
most likely that the female bends enough to lay directly into its
pouch. The pouch of the Echidna is just an arrangement of skin folds.
The male has a "Pouch" as well, and it is difficult to determine the
sex of an Echidna.A baby Echidna is called a "Puggle". The
Puggle may only weigh about 3 grams (a tenth of an ounce) straight
after hatching but can increase to 180 grams (6 ounces) after 60 days.
Bringing Up the Puggle
The
baby Echidna lives in its mother's pouch for about seven weeks, feeding
on the milk from the two milk patches in the pouch and growing very
fast. When the Puggle's spines start to harden the mother Echidna
transfers the Puggle to a nursery burrow. She returns every five to ten
days to feed her Puggle. After about five months the mother stops going
back and the young Echidna is by itself. The Echidna is unusual among
the mammals in not appearing to instruct its young.
Food
The
Echidna's main food is termites. This insect is very common and
widespread in Australia. Echidnas will also eat ants and other
invertebrates including worms and grubs.
Predators
There were not many native predators of the echidna. Wedge-tailed Eagles will sometimes eat an Echidna, and Goannas can eat the Puggles while they are in the nursery burrow.
However there are several introduced predators of the Echidna.
The first one was the Dingo. This was a domestic dog brought in by the
aboriginal people of Australia many thousand years ago and went wild.
More recently there have been other dogs, but worse than these are the
cats and foxes. Some of these introduced predators have learned
techniques for dealing with this prickly animal.
Echidnas
are very fast diggers and on soft ground will escape their predators by
digging. On hard ground the Echidna will roll up into a ball, wait and
hope the predator will go away. The spines of the Echidna are not as
fearsome as those of the porcupine, but still quite sharp. Humans
should not handle an Echidna without suitable protection or knowledge.
Puncture wounds from the spines can get infected. Also, Echidnas should
not be relocated without good reason. The animal could be a female that
is feeding a Puggle in a nursery burrow. Moving the adult to another
area could result in the death by slow starvation of the baby.
As well as this, the mother may try to get back to its baby and be killed on the road.
Habitat
Echidnas
live in a very wide variety of places such as the dry interior of
Australia, the tropical rain forests and even the cities. The basic
requirement of Echidnas is termites.
Fire
In Australia
there are sometimes devastating bush fires that kill thousands of
animals. The Echidna cannot run fast. When there is a fire they usually
only succeed in getting about a metre (3 feet), but they do this in the
right direction. They dig straight down and usually survive even a very
bad fire.
Brain
The Echidna's brain's prefrontal lobe is larger in relation to the animal's size than any other animal, including human beings.
Body Temperature
Like
all mammals, Echidnas maintain a body temperature. The normal body temperature of the Echidna is 33̊ (91̊ F); this is lower than that of
any other mammal. The Echidna also allows its body temperature to vary
more. An Echidna can still be active with a body temperature of 28̊ C
(82̊ F).
Hibernation
The Echidna can hibernate. It
will allow its body temperature to fall to 4̊ C (39̊F). The Echidna's
breathing rate drops to about one breath every three minutes.
Dreaming
Dreams occur in Rapid Eye Movement Sleep (REM sleep).
It
used to be believed that the Echidna was the only mammal that does not
dream, but further study has found that the Echidna does dream, but
only at some temperatures.
Types of Echidna.
There are two species of Echidna: the Short Beaked Echidna, Tachyglossus aculeatus which lives in Australia including Tasmania, and in the New Guinea lowlands, and the Long Beaked Echidna,Zaglossus bruijnithat lives in the New Guinea highlands.
There
are five sub species of Short Beaked Echidna including the Tasmanian
sub species which is bigger than the mainland ones and has fur longer
than its spines.
Sources
Robert, our SeaLink driver on a tour of Kangaroo Island, told us some interesting facts about Echidnas. Echidna Love Trains - June - Scribbly Gum - ABC Science Online was very useful in writing this article, as was the "DPIW - Short-beaked Echidna" article on the Tasmanian Department of Primary Industries and Water website.
For some of my articles, I have done accompanying "Slide shows". I will not do one for Echidnas because the set of pictures: photos is so good that to put my own online would be an impertenance.
Environmental Disasters 
