Mary Gardner
We found it dead on the sand near the mouth of the Tallow’ the woman said.
The corpse stunk a little but I hardly noticed. I was so astonished. What was this platypus doing here? Who knew there were any around this side of Byron Bay? How did it live? As importantly, how did it die?
The dark fur of this aquatic mammal is so thick and soft to touch. The outer layer has long thin shiny hairs covering an inner one that is shorter, woollier and denser than the fur of a polar bear. Together they trap air close to the skin. When a platypus swims, some of the trapped air bubbles trail behind it. The fur keeps the animal a comfortable 32°C while submerged for up to twelve hours.
The bill feels rubbery. Not until 2003 did science appreciate how it works. The skin is full of pores that hold two types of electro-sensors. One type has a flexible rod and the other is filled with mucus. Both sensors are connected to the trigeminal nerve and then to the brain.
This sixth sense is how platypus hunt underwater. Diving and digging for up to two minutes, holding its breath, its eyes, nostrils and ears all closed, it locates yabbies, shrimps, shellfish and frogs in the murky sediments.
This platypus is a male. The head of its penis has two glands with the left one the larger one. This would complement the female who has two ovaries but only the left one is functional.
The female lays eggs that she incubates in a deep burrow in the banks of a waterway. Milk for her platypups oozes through milk patches on her belly. The milk is made of unusual proteins that the CSIRO says include a new type of antibiotic – only discovered in March this year.
The male also has two hollow spurs on its back legs. Each delivers a unique and painful venom, strong enough to kill a small dog. The quantity of venom produced is much greater from August till October. This is the time that males will wander far overland seeking females.
I look at the webbed feet. Anatomists point out that the platypus on land does ‘knuckle walking’, as do chimpanzees and gorillas, they walk on their flexed fingers.
How did this male, of a freshwater species, wind up almost on the beach at Tallow? Each day of his life, this male would have hunted in a home range of up to seven kilometres of waterway with up to fifteen hectares of foraging area. He would range up to four kilometres a night. Could he have lived somewhere upstream?
Maybe he was like those brash young males with radio tags in the Yarra River. One moved forty kilometres over eighteen months and another forty-eight over seven months. Still another travelled ten kilometres overnight. Was he originally part of the mob often seen around Coopers Shoot or at the ‘Bangalow waterfront’? Or was he a senior: reaching ten years of age?
A female platypus would only range over about four kilometres. September is the silly season of mating for these animals who usually are quite shy and solitary.
I feel bamboozled trying to imagine the lives of platypus of either sex around here. These animals are badly affected by urban or agricultural changes to waterways. When an area has more than 11 per cent covered over with hard surfaces such as roads, roofs and parking lots, their numbers drop.
Rising concentrations of dissolved nitrogen, phosphorus or heavy metals also badly affect them. Rapid increases in flow from conventionally engineered stormwater systems and many agricultural drains also wash out the animals or their food. Did the recent opening of Tallow ICOLL play any part in this?
A tissue analysis might reveal the toxin burden this platypus carried. A DNA analysis might identify some relatives. Maybe a nitrogen isotope sample of the tissues compared with tissues from some of its food animals from various nearby waterways might reveal where it foraged.
An autopsy might reveal if the thick fur is hiding puncture wounds or a broken back from a dog or fox. Dying or dead, it could have floated down in the rush of the Tallow waters and ended up on this far shore.
Any of these investigations require specialists and funding. Likely none of this will ever be done. Still…
‘Let’s put it in the freezer and call National Parks and Wildlife.’ I said. ‘Maybe they can get a proper examination of the poor little thing.’
• Any sightings please email [email protected].
Has the platypus autopsy taken place ?
Would like further report if poss.