Echidnas

This is a random collection of information and observations that I put together as a presentation prior to one of the echidna sweeps (counts) in Mulligans Flat.

I’m gettin’ real close

(and i’m spiky)

Echidnas are monotremes (this means one hole - the cloaca is used for urination, defecation and reproduction). This is a type of mammal (other types are the placentals and marsupials), and like all mammals, echidnas are endothermic, have fur, and produce milk. Unlike other mammals, echidnas (and also platypus) lay eggs rather than giving birth to live young.

The snout is probably the most sensitive part of the echidna. Loaded with sensory receptors including smell (very very good), touch, electroreceptors and another sensor unit that picks up ground vibrations (mechanoreceptors). The skin on the snout is tough and leathery like a reptile skin and is kept moist by bubbling mucous through the nostrils. The snout is also one of their primary digging/foraging tools, and is used to prod the ground as well as pry apart logs etc.

The tongue is long (about 20cm) and quite sticky and very mobile. It is able to be steered around the ant and termite holes and tunnels. Can be used about 100 times per minute.

The echidna has no teeth, but rather a hard plate on the upper mouth to help it grind the food to a liquid pulp.

The ears are very very sensitive, and particularly good at low frequency sounds. They react quickly to sharp noises but don’t mind gentle low sounds.

Their eyesight is reasonable but not great. They have a protective layer that is keratinised to help protect it from ant bites as well as accidental poking with spines (which does occur during mating and even self spiking when curling into a ball).

I have found echidnas to be very intelligent, and understand that they have a large part of the brain dedicated to mapping and possibly farming (they know where ant nests are in their home range, and don’t completely destroy them but rather eat some ants and then move on). I am convinced that the echidnas that I regularly visit have started to recognise me, and are very willing to approach me.

Their forelimbs are extremely stout and robust, specialised in digging and ripping apart logs and moving rocks. They have very long spatula like claws to assist with digging.

The hind limbs are almost reversed, and are very good for scratching all over with their very long grooming claws.

The body is obviously covered in short, stout spines which vary in thickness from a thick coarse hair to about 7mm thick. The spines are made from keratin and are essentially the same as hair. The ends of the spines are very sharp. Spines are occasionally lost.

The tail is also covered in spines and is able to be curled right round to complete a very spiky ball.

It is very difficult to tell the difference between a male and a female in the field. The only visible difference is the presence of a non-venomous spur on the male’s rear ankle.

Echidnas have fairly large but well defined home ranges. They don’t defend the home range, so it’s not really a territory, and there will usually be about seven echidnas in any overlapping home range. Some individuals don’t really observe home ranges and wander freely around visiting different sites, while others stay put for years. 

In August through to October the males will follow females around and form echidna trains. There can be a number of males following a single female, with vigorous pushing and shoving while jostling for position close to the female, sometimes gently nudging the female. The females secrete a strong smelling pheromone which the males seem to follow from long distances. Train formation varies from year to year, and is known to vary with climate. While there weren’t many trains spotted this year, there are definitely a few long-term breeding pairs in Mulligan’s Flat.

Eventually it comes down to one male who is permitted to mate with the female. Mating lasts for about half an hour to an hour, and is quite a secretive sort of affair.

Echidnas usually lay a single egg which is placed in a loose pouch along the female’s abdomen. It eventually hatches and the young puggle finds its way to the mother’s milk producing patches on her relatively bare abdomen. She fusses over the young for several weeks until at about 12 weeks it starts to develop spines. She then deposits the puggle in a nest and seals the entrance with soil while she goes off to feed. She returns about once a week to excavate the entrance, feed the puggle and then bury it again. This seems to be a good method for protecting it from snakes which are the main threat. On her final visit, she feeds the puggle and wanders off without sealing the entrance, and then the young echidna is on its own.

All food sources are found underground (ants, termites some small invertebrates that can fit through the small mouth opening)

They can eat about 40000 ants and termites each day

Excellent at burrowing and can easily burrow straight down and disappear quickly. Can also easily push through most fences.

Able to operate quite well even after losing sight in both eyes

Able to lower body temperature to survive periods of low food availability, climate extremes and even bushfires. Generally about 10 degrees lower body temperature than other mammals.

Body temperature can go down to about 5 degrees and heart rates slow to only a few beats per minute.

Able to tolerate extremely low oxygen environments.

They are quite good swimmers

Some tips to help with finding them

They have an excellent sense of smell and hearing and also push their snout against the ground to pick up low frequency vibrations, so they can smell and hear you coming. They tolerate low gentle sounds, but startle easily with sharp sounds (like a snapping stick)

They have poor eyesight, but surprisingly good ability to see colour (unconfirmed, but based on number of receptors)

Very intelligent, and have a good ability to map and remember

When threatened the sharp spines are quickly put into action, helped by a muscle around the shoulders which can quickly shrug the spines up around the head. 

Strong digging ability allows them to excavate straight down while still being protected from above by their spines.

Activity levels vary throughout the day. Most start off slowly, and aren’t really seen before mid morning. As the day warms up they move out into the open and spend the middle part of the day foraging. They seek shade if it gets too hot.

If they are startled they quickly look for the nearest log, tree or rock to hide against.

Soooo, what does this all mean for approaching echidnas?

In the early part of the day expect to find them hiding at the base of trees or logs. Later in the day they will be quite apparent and easy to spot out in the open.

As with all wildlife, it’s best to sit patiently and let them approach you as they feel comfortable, but if you have to approach them do it very slowly and quietly.

I find that they like being spoken to in a soft low voice. Try not to snap twigs underfoot. Don’t touch them as this tends to startle them.

If they do startle, wait quietly and they will often relax after a few minutes (the snout will slowly peek out and sniff the air).