Three Venomous Mammals That Will Blow Your Mind

Have you ever wondered what it would be like to dispatch your enemies with no more than their keen knowledge that you possess a deadly venom? No? Oh. Well, nevermind then.

Anyway, as it turns out, there are in fact venomous mammals on this planet right now! (Which is the coolest thing you’ve learned all week and we both know it.)

via Wiki. Credit: E. Lonnon

1. Male Platypus (Ornithorhynchus anatinus)

That’s the foot of a platypus that you’re looking at in the photo above. And protruding from that foot is a small, sharp spike. Both males and females have spurs on their ankles, but the females’ eventually fall off. The males’ spurs, however, are connected to venom glands higher in the leg. The venom is a cocktail of proteins, some of which are related to proteins in the venom of snakes.

From the Stanford Neuroblog – click for more info on platypus venom.

According to a study in the journal Nature, these monotremes (egg-laying mammals) have some reptilian traits, showing that they split from other soon-to-be-mammals way earlier than placentals (that’s us, with our wombs and placentas) and marsupials (mammals that give birth in pouches, like kangaroos). The study lead, Wesley Warren of Washington University in St. Louis, Missouri, said, “That early divergence means platypus genes carry information from a transitional point on the evolutionary time line leading from reptiles to mammals.” Which helps us to understand why the platypus was more likely to develop venom proteins. According to the study, the platypus genome also shows that lactation developed long before live birth, two things that I’d always assumed went hand-in-hand.

Like reptiles, the platypus lays eggs and has a cloaca (one opening for the excretory and genital tracts), and the brain does not have much in the way of corpus callosum (brain tissue that allows communication between the two sides). Like mammals, the platypus lactates, has hair, and spends a long time with its young. This animal has also evolved a sense of electro-reception, which allows them to discern live food in murky, muddy river bottoms. When animals are disturbed, their muscle contractions emit tiny electric pulses, which that fleshy, sensitive “beak” on the front of the end of the platypus can detect.

The platypus uses its venom not for subduing prey, but for self-defense. While the venom is strong enough to kill only smaller animals, it does induce excruciating pain in larger animals like humans, according to stories told by those tagged by the beastie.

2. Four species of Shrew (Soricidae spp)

The next venomous mammal on our list is the little-known shrew. Shrews are small, about the size of a mouse, but they’re not rodents. They’re insectivores and lack the big biting front teeth that identify rodents. They have small, sharp, and spikey teeth instead, and eat mostly invertebrates with only some plant matter mixed in.

Short-Tailed Shrew. Credit: Jennifer Edalgo

The four venomous shrew species include the Northern, Southern, and Elliot’s Short-Tailed Shrew and the Eurasian Water Shrew, all of which appear to have a toxic bite. There isn’t a great deal of information on shrew venom – I can’t find any info on whether the shrews have grooved teeth for delivering the toxins like a snake, or if the toxins get mixed in with the saliva in the salivary glands.

What does seem clear is that shrews are ferocious little beasts, and they definitely use their dangerous bite for subduing prey. They focus mainly on invertebrates, but may also be able to immobilize other vertebrates. Their venom seems to paralyze the victim but not immediately kill it, which allows the shrew to cache it for later use! Shrews have a very high metabolism and heart rate, which means they need to eat constantly, so storing fresh food is a nifty strategy for them. They also have no problem nipping at humans, but the human reaction to a shrew’s bite sounds minimal compared to the platypus. Another awesome fact about shrews? Some species, like the Northern Short-Tailed, actually utilize echolocation to explore their environments. They emit ultrasonic clicks and have a good sense of smell, which makes up for poor eyesight!

3. Solenodon (S. cubanus & S. paradoxus)

Last, but not least, we have a unique creature called the Solenodon. Solenodons are in the same order as shrews but are in a different family. They resemble shrews with their large snouts and long, furry bodies, but are much larger.

I love his toupee. Credit: Eladio Fernandez

Solenodons are ancient critters that are similar in appearance to what our mammal ancestors looked like at the end of the age of dinosaurs. Apparently solenodons do have grooved lower incisors for delivering venom, and use it like shrews to immobilize prey. They also focus mainly on invertebrates with some vertebrates and plant matter thrown in for variety. Solenodons – get this – have a ball and socket joint at the base of that long snout to improve flexibility! For more info on this rarely-seen creature, check out this article on The Last Survivors. You can also check out NatGeo’s video featuring footage of a solenodon that was captured (and then released, after a checkup and filming) in the Dominican Republic.

Thanks so much for joining me, I hope you learned something.

Now, does anyone else suddenly have the urge to watch Princess Bride…?


Posted on October 13, 2010, in Fauna and tagged , , , , , , , , , , , , , . Bookmark the permalink. 7 Comments.

  1. Hi,
    Very good post, good information, I enjoyed the read.
    Yes the old Platypus is a real come in sucker, they look so cute, and devine when seen swimming in a creek, but they are dangerous. Being an Aussie, I learnt about the dangers at a very young age (a long, long time ago). You don’t hear much about them at all, it was good to see them in your post.

  2. Thanks! In the US we don’t get the opportunity to learn much about Australian animals and we really should – the differences in groups really highlight all the awesome things about mammals and evolution. Thanks for the comments! :)

  3. This knowledge, I have found, is the best way to quickly earn $20 making bets around any campfire or bar table.

  4. Hi Your picture of the platypus spur and the diagram of the venom path is awesome. I’m doing my 5th grade independent inquiry project on venomous mammals and I’d love to use these pics on my poster board and prezi page. May I? Zack

    • Hi there Zach! Thanks for asking, but those pics aren’t mine – if you click on the image you want to use, it should take you to the original site it comes from. You should be able to find author information there. Let me know if you have any trouble with the links!


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