The Oldest Surviving Mammal on Earth

Every day we see calmly wandering echidnas (Tachyglossus aculeatus) as we ride around Raymond Island, here in the Gippsland Lakes region of Victoria.

I am amazed that we see them so often. These unusual animals are typically quite elusive. They must feel quite safe, because they don’t seem to be fussed in the streets of the little village, or even as we quietly watch them feed. They come close to the house too.

Monty and Maia chatting to the Echidna near the house.

I was fascinated yesterday as I watched one poking holes in the soil with it's snout on quite hard grassy soil on the roadside. I was thinking how effective they were at opening the soil for the next rain. Later I noticed another fossicking in the leaf litter before disappearing into the undergrowth. I realised how important these wild and 'messy' spaces are for them.

Echidna on the streets of the Raymond Island Village digging with her snout for insects. (I actually can't tell if its a girl or boy)

Fresh echidna digging holes.
The kids and I have become so enchanted by their their lovely little faces and antics. We realised we only knew a little about them so we decided to investigate. We found some really interesting facts about these curious creatures, and thought they would be interesting to share.

A great natural defence.

Two dozen interesting facts about echidnas.

  1. Echidnas are the oldest surviving mammals on the planet today (evolved 20-50 million years ago).
  2. Echidnas are egg-laying mammals (monotreme) like the platypus - soft leathery eggs about 2 centimetres in diameter.
  3. Echidnas keep their young in pouches (like kangaroos) for about three months and wean them at 12 months.
  4. Echidnas are long lived - up to 50 years in captivity, and reports of 45 years in the wild, but usually 10-15 years.
  5. Echidnas have very large brains for their body size - the largest prefrontal cortex of any mammal
  6. Echidnas have the latest eye lens of any animal giving it the longest focal length.
  7. Echidna’s ears are sensitive to low-frequency which is ideal for detecting termites and ants underground.
  8. Echidnas are around 30-45cms and weigh 2-5kgs
  9. Echidnas have the lowest body temperature of any mammal - 32 celsius.
  10. Echidnas have a slow metabolism - the lowest energy-consuming mammal.
  11. Echidnas hibernate in winter. They can slowing their heartbeat to 4-7 beats/minute and taking a breath every three minutes
  12. Echidnas are covered in fur and spines - the 5cm spines are actually modified hairs.
  13. Echidnas eat ants, termites, grubs, larvae, worms.
  14. Echidnas are electroreceptive - the echidna has 400-2000 electroreceptors on their snouts (platypus have 40,000 on their bills) .
  15. This special snout (also called a beak) senses electrical signals from insect bodies. When it detects prey, it uses its sharp claws to dig into the soil then lick them up with its tongue.
  16. Echidnas are toothless - the use their fast 18 cm sticky tongue (Tachyglossus means ‘quick tongue’) to catch ants, termites, worms and insect larvae. They break down food with hard pads on the roof of their mouth.
  17. Echidnas are found all over Australia including rainforest, dry sclerophyll forest and arid areas. 
  18. Echidnas are able to survive extreme temperatures however they have no sweat glands and cannot pant, therefore need to protect themselves from high temperatures by digging into the soil.
  19. Echidnas are found only in Australia (short nosed) and New Guinea (long-nosed). 
  20. Echidnas are usually solitary animals 
  21. Echidnas are not often seen, but are classified as ‘common’ 
  22. Echidnas are not territorial. In some areas their range can be 50 hectares or more.
  23. Echidnas are protected in Australia by Law.
  24. The echidna is featured on the Australian 5 cent piece

Echidna puggle. Image: Perth Zoo

Echidna Threats

The key threats to echidnas are dog and cars. Thankfully here, traffic is slow and limited on the island, and people seem very responsible with their dogs, particularly as this is a koala reserve too. When echidnas need to protect themselves, they curl up into a ball with just their spines facing out.

Habitat loss is also a problem for echidnas in populated areas of Australia. They need fallen logs, tree stumps, rocks, leaf litter and debris. We often clean things up too much. Keeping the under storey is also important as it provides cover for echidnas as they move around. I often watch an echidna around my parent’s house disappear back into the dense bush after it’s had a wander here.  It’s good to remember too that these logs, leaf fall and rocks provide good habitat for things echidnas like to eat.

Some further reading on Echidnas

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