Echidnas are the oldest surviving mammal on the planet today

Biology

Echidnas are the oldest surviving mammal on the planet today, with five sub species of short-beaked echidnas, as well as their close relatives, the long-beaked echidnas; found in New Guinea. There are four subspecies of short-beaked echidna found in Australia.

Distribution

Echidnas are found all over Australia including regions of rainforest, dry sclerophyll forest and arid zones. They are able to survive extreme temperatures, with localised adaptions such as denser fur, in several sub species.
Although echidnas are seldom encountered, they are widespread and classified as ‘common’. 

Home range

Echidnas are solitary animals and are not territorial. They have overlapping home ranges which vary greatly in most centres their home range could be as large as 50 hectares. 

The short-beaked echidna is classed as a myrmecophage (ant and termite specialist); however, they will also eat larvae of other invertebrates such as the Scarab beetle, as well as other adult beetles and earthworms. The size of the prey is limited by the gape of the echidna’s mouth, which is around 5mm. The tongue can dart out and extrude up to 18cm to catch its prey, with the help of its very sticky saliva. 

To find its food the echidna is extremely reliant upon its snout. It will forage through the leaf litter poking its snout into rotting logs and other potential food sites, until it can detect either the smell or the electrical impulse of its potential prey. It will use its powerful forepaws to rip open logs to reach its prey, or may simply lie on top of a non-aggressive ant mount, and wait until the ants race over its awaiting tongue; whereby the tongue is quickly withdrawn into its mouth.

Anatomical Features

Spines and fur 
The echidna’s spines cover its head, back and tail with only a covering of fur on its ventral surface. The spines are generally straw-coloured with black tips, and are both strong and sharp; the purpose of these spines being purely for defense.
Echidnas in colder climates have less spines and thicker fur.   

Weight and size
Short-beaked adult echidnas can weigh anywhere between 2 to 7kgs. 
Neither the size nor weight of an echidna is a useful indicator of age, maturity or gender. It is therefore very difficult to tell if an echidna is a male or female unless a veterinarian conducts an ultrasonography.  
It is believed that female echidnas become sexually active at around 5 years of age and normally have their first puggle at age 6 or 7.  Male age at sexual maturity has yet to be determined through research.

Reproduction

Echidnas spend most of the year alone however when a female comes into season (usually towards mid to late winter), ‘trains’ of echidnas may be seen for up to a month. 

The female is always at the front of the ‘train’ and she may be followed by up to 10 males.  The male who endures the courtship period, and remains closest to the female, may be the lucky one and have a chance to breed, when the female is receptive.

Echidnas are ‘monotremes’ each mean that they lay an egg.  The egg remains in the female reproductive tract until it is about the size of a grape. The egg is oval in shape and weighs between 1.5 – 2 grams. Once the egg has been laid, it remains in the females pouch for a further 10 days.

The baby echidna (called a ‘puggle’) hatches from the egg by using its egg tooth and pull its way along the mother’s hair into the pouch area. 

During this period it is believed that the female echidna starts to construct her nursery burrow, which normally consists of a metre long tunnel with an enlarged area at the end.

The female echidna does not possess nipples to feed her young. Instead she has milk patches within her pouch, whereby up to 150 pores secrete the milk onto specialized hair follicles. The puggle suckles the milk at a rapid rate, whilst encouraging milk letdown through ‘nuzzling’ at the pouch area.

Once the puggle starts to grow spikes (around 50 days of age), it will be removed from the pouch and left in the burrow whilst the mother forages for several days on end.  However, the mother continues to suckle her young when she returns to the burrow every 4-6 days, until the Puggle is around 200 days of age. 

When the baby is around 200 days of age, the mother will return to the burrow, dig the young out of the nesting area, and then emerge from the burrow with her young echidna. She will feed it one last time, and simply walk away leaving the burrow entrance open. She will not return to the burrow again, hence avoiding any further contact with her young.

It is important to consider the time of year for rehabilitating female echidnas, because they may be tending young either in their pouch or in a burrow. Therefore, it is essential that they be returned to their place of rescue as quickly as possible.

Rescue Techniques

If an injured or sick echidna is reported, they should be taken to a wildlife veterinarian immediately for a full and thorough assessment.

Echidnas are very spiky and hence handling can be tricky.

Echidnas will often avoid capture by digging themselves into the soil or other tight spots. It is very difficult to remove them without digging them out physically. Digging should be far enough from the animal to avoid further damage to limbs, snout or other body parts. Do not use a shovel to dig the echidna out – use your hands.  To remove the echidna it is essential that the hole dug allows the rescuer access to the underbelly region of the echidna. To remove the echidna, place a hand just behind the forelimbs on the underbelly region.  Echidnas can also be picked up when rolled into a ball with thick leather gloves to protect the hands.

A different method of handling can be used if the echidna is on hard ground, which makes it difficult to dig either side of the echidna to access its underbelly. One hind leg can be grabbed by the ankle and the echidna gently lifted off the ground until the second leg can be held. Do not use this method of handling if the echidna is suspected of being injured.

For those that are not experienced with handling echidnas, the use of a pair good quality leather gloves are strongly recommended.  Alternatively, use a thick towel (folded over) and wrap this around the echidna to pick it up.  The towel method though makes it difficult to assess the back of the echidna.

Keep in mind at all times that echidnas are escape artists and climb extremely well. Therefore, echidnas should be contained in a tall plastic container with a secure lid (holes must be drilled into the lid for ventilation). Layers of towels should be placed on the base and in hot weather, covered ice packs may also be placed alongside the container to keep the temperature below 25oc to avoid overheating.

Common Injuries

The most common reasons that echidnas come into care is due to motor vehicle accidents or being bitten by a dog.

Motor Vehicle Accidents

The echidna’s thick spiny covering can obscure many injuries, and this coupled with the inability of echidnas to vocalise, means that very often, the seriousness of their injuries is overlooked.  All echidnas that have been hit by a car, MUST receive a full veterinary assessment by a wildlife veterinarian.  The most common injury sustained by echidnas is a fractured beak and often this is not easily discernible.  All echidnas that have been hit by cars should undergo radiographs to ensure that there are no fractures.  

Many echidnas that have been hit by cars, will wonder off the road and many people will assume that they are okay.  If they have sustained a fractured beak, they will most likely die from suffocation (as the beak swells) or will starve to death as the receptors in their snout have become damaged and they are unable to locate food. 

Dog Attacks

Any echidna that has been bitten or ‘played with’ by a dog should receive veterinary attention.  They can offer sustain serious bruising and internal injuries and must be fully assessed by a wildlife veterinarian. 
If you are interested in learning how to rescue and care for echidnas, enrol to complete an echidna workshop through The Northern Wildlife Carers 1800008290. 

Caring for injured and orphaned echidnas requires specialised skills and is generally undertaken by wildlife rehabilitators that have several years experience with caring for wildlife.