The world can be a terrible place. Sure, there are the finer things that make life worth living – puppies, spooning, hoppy beer, etc. – but there are also things that make you wonder, ‘Now why should anyone ever have to endure this?‘ I recall being a child, growing up on the mean streets of Kansas City, MO, it was a struggle just to get an education. There were bandits that set up a ‘toll’ to cross the bridge to get to the school, and if we didn’t have any pence to put in their pouches, well we’d have to fight our way into the classroom (see map below, of Lincoln College Prep middle school). Getting home in the afternoon was even worse. There was an Iron Maiden. And this thing.
I thought my midwest urban childhood was tough, until today when I read about “cane toads” (Rhinella marina) (below, right). Now, toads in general are odd animals. They’re vertebrates, with a sweet bony spine and skeleton, like us humans and wicked-pisser mammals. But they’re also not like us (“NLU,” as my sweet, politely diabolical grandma would say). Not like us at all. When a human is a baby, she or he looks more or less like an adult, albeit much smaller and cutely misproportioned. But a toad – well, amphibians just have a totally different life plan. Toad babies are these “tadpoles” (or “pollywogs” if you’re feeling especially cavalier and sassy) that don’t have a body with a head and four limbs that can be used for being awesome. Instead, pollywogs are these fat embryo-ish bodies trailing along a slithering tail. Limbs eventually form from tiny buds and the tail is lost. But superficially, the panning out of toad ontogeny looks like giant sperm deciding to become frog-like abomination unto something. So toads are already not quite right from the get go.
But this one species, the cane toad, has tadpoles that EAT THEIR EGG SIBLINGS and EMIT A CHEMICAL THAT STUNTS THE DEVELOPMENT OF THEIR BROTHERS and SISTERS. In the history of human society there have been a number of stories of family eating family, but there is nothing quite like this. It’s a mix between the child-eating Kronos (or Roman “Saturn”) or Thyestes (though his was accidental), and Cain and Abel from the Bible that’s such a smash with the Judeo-Christians, or Romulus and Remus from the mythic founding of Rome. [Hey I guess my Classics BA has come in handy after all!]
So next time you’re feeling down and out, upset with the hand the great Dealer has dealt you, just be glad you weren’t a cane toad. Because then you’d’ve either been eaten/murdered by your older sib, or you’d’ve eaten/murdered your siblings. Yikes.
Feelings aside, this toad presents a very interesting case study. It will be interesting to uncover the biochemistry and genetics behind how the older pollywogs stunt the development of their little brothers and sisters. I can see this really helping with an understanding of how growth and development are controlled and inhibited, and possibly even how they can be manipulated. It would also be interesting to see if in the evolution of these species, there arose any biochemical defenses expressed in eggs and young larvae against older sibs’ fratricidal fragrances, or if it was simply a 1-sided battle.
Life is a funny, funny thing.
Works Ci-toad [sorry for the terrible pun 😦 ]
3 thoughts on “And I thought I had it bad (or, "Toad terrors")”
It is possible that this evolved to prevent other species eggs and tadpoles form dominating the site, with sibling consumption being secondary
It should probably be noted that this behavior probably evolved due to successful elimination of other species eggs/tadpoles in the vicinity, and that sibling elimination was secondary and incidental.DDeden
It should probably be noted that this behavior probably evolved due to successful elimination of other species eggs/tadpoles in the vicinity, and that sibling elimination was secondary and incidental (otherwise it would result in reduced species population).DDeden