Remember the platypus


in Geek stuff, Science

The Platypus is a strange and intriguing creature. Some of the odder things about it:

  1. Males can inject venom from spurs on their ankles. The venom will not kill humans, but is extremely painful and heightens overall sensitivity to pain for a period between a few days and several months.
  2. They have ten sex chromosomes, out of a total of 52. Males are ‘XYXYXYXYXY.’
  3. They swim using only their two front legs, though the back two are also webbed.
  4. Only the left ovary of females is functional.
  5. They have no visible ears.
  6. They only use their eyes while above water.
  7. Underwater, they can detect electric fields generated by muscular contractions.
  8. They lose their three teeth before they first leave their mother’s burrow.
  9. They forage for twelve hours a day.
  10. They have a body temperature five degrees lower than most placental mammals.
  11. Females lactate through pores in their skin. Milk pools in grooves located on their abdomens.
  12. The DNA of one female – named Glennie – has now been sequenced by researchers at Oxford.

I recall reading that Australia has three types of animals: the venomous, the bizarre, and sheep. The platypus scores highly on the first two counts.

{ 6 comments… read them below or add one }

Milan May 9, 2008 at 10:13 am

“There is nothing quite as enigmatic as a platypus”

May 9, 2008 2:09 AM

It turns out if it looks like a duck it’s partly a duck. A bunch of scientist got together and set about to decode the platypus genome, and guess what!?! “What we found was the genome, just like the animal, is an amazing amalgam of reptilian and mammal characteristics with quite a few unique platypus characteristics as well”. “You have got these reptilian repeat patterns and these more recently evolved milk genes and independent evolution of the venom. It all points to how idiosyncratic evolution is.” “We have microRNAs that are shared with chickens and not mammals as well as ones that are shared with mammals, but not chickens.” Also, apparently, male platypi have venomous spikes on their heels that can kill dogs!

Milan May 9, 2008 at 12:32 pm

Top billing for platypus at end of evolution tree

Monotreme’s genome shares features with mammals, birds and reptiles.

Susan Brown

A draft sequence of the platypus genome reveals reptilian and mammalian elements and provides more evidence for its place in the ancestral line of animal evolution.

The platypus (Ornithorhynchus anatinus ) is endemic to Australia and one of nature’s oddest creatures, seemingly assembled from the spare parts of other animals. The semi-aquatic monotreme is a venomous, duck-billed mammal that lays eggs, nurses its young and occupies a lonely twig at the end of a sparse branch of the vertebrate evolutionary tree.

Genome analysis of the platypus reveals unique signatures of evolution

Nature 453, 175-183 (8 May 2008) | doi:10.1038/nature06936; Received 14 September 2007; Accepted 25 March 2008

We present a draft genome sequence of the platypus, Ornithorhynchus anatinus. This monotreme exhibits a fascinating combination of reptilian and mammalian characters. For example, platypuses have a coat of fur adapted to an aquatic lifestyle; platypus females lactate, yet lay eggs; and males are equipped with venom similar to that of reptiles. Analysis of the first monotreme genome aligned these features with genetic innovations. We find that reptile and platypus venom proteins have been co-opted independently from the same gene families; milk protein genes are conserved despite platypuses laying eggs; and immune gene family expansions are directly related to platypus biology. Expansions of protein, non-protein-coding RNA and microRNA families, as well as repeat elements, are identified. Sequencing of this genome now provides a valuable resource for deep mammalian comparative analyses, as well as for monotreme biology and conservation.

zoom May 9, 2008 at 10:58 pm

The platypus is my favourite animal.
Do you know why only the left ovary is functional?

Milan May 10, 2008 at 12:12 pm

It’s certainly rather odd, isn’t it?

It suggests that a mutation emerged at some point and proved beneficial enough to spread through the population.

Sarah May 10, 2008 at 1:59 pm

What is the plural of platypus?
I don’t think the venom is so terribly odd, at least in a context where there are a very large number of highly venomous critters around. Presumably anything that isn’t threatening or hiding most of the time (eg. wombats in holes, possums up trees) would become a preferred prey for any nearby carnivores. Nontheless, the platypus does seem very unusual & I have a soft spot for them on that account, perhaps helped along by the toy platypus my brother once owned (& which he, with typical imagination, named Platty).

Milan May 10, 2008 at 9:28 pm

I think the most correct plural form of octopus is octopodes.

As such, I would guess platypodes.

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