3am on Sunday morning and I’m getting ready to join a small group of volunteers counting Platypus in Moggill Creek. The early start is required as Platypus are most often seen near dawn or dusk. I have never seen a Platypus before so have decided to volunteer for the Moggill Creek Catchment Group’s Annual Platypus Survey which has been running for 6 years. The number of sightings has varied from a maximum of 15 down to only 6 last year.
The animals are surprisingly small – approximately 40 to 60 centimetres in length and typically weigh 1.2-2.6 kilograms. They float very low in the water, with a slightly higher profile marking the location of their head and rump which causes the conspicuous bow wave created as they paddle along the surface. A platypus can remain underwater for a long time although when searching for food, they usually stay submerged for less than a minute before returning to the surface to breathe. They can also reduce their need for oxygen when diving by lowering their heart rate dramatically; from more than two hundred beats per minute to less than ten beats per minute.
The platypus is a warm-blooded mammal with a typical life span, in the wild, of about 4-5 years for males and 6-8 years for females. The longest reliable age record for a platypus in captivity is 17 years. A female platypus produces a clutch of one to three eggs in late winter or spring which are 15-18 millimetres long and have a thin, leathery shell, like those of snakes and lizards. The mother is believed to incubate them between her lower belly and curled-up tail for a period of about 10 or 11 days as she rests in an underground nest made of leaves or other vegetation collected from the water. A female platypus does not have nipples instead, a rich milk is secreted from two round patches of skin midway along the mother’s belly. It is believed that a baby platypus feeds by slurping up milk with rhythmic sweeps of its stubby bill. When the juveniles first enter the water at the age of about four months, they are nearly (80-90%) as long as an adult.
I was very surprised to read that the platypus is the only Australian mammal known to be venomous. Adult males have a pointed spur (about 15 millimetres long) located just above the heel of each hind leg, which can be used to inject poison produced by a gland in the thigh (the crural gland). It is presumed that males mainly use their spurs when competing for mates or breeding territories, although if provoked, a male platypus can use his spurs as a defensive weapon. In the days when platypus were shot for their fur, dogs were sometimes killed after being sent to retrieve a wounded male from the water. It’s not considered to be life-threatening to a healthy human although I’m told spurring is very painful.
I turned up at our meeting place at 4.30am and along with 4 others was taken to our individual sites on the river bank. It was a little daunting as it was still dark, the grass was long and my torch battery was very weak. I am always conscious of the danger of snakes, particularly at this time of the year so walked to my location very carefully.
After sitting still and without making any sound for two hours I was indeed fortunate to see two platypus. I was very pleased with this and glad that I had made the effort to come. I decided to forgo breakfast with the group and headed home to enjoy the rest of Sunday morning leisurely reading the papers.