Solenodon, ancient relic of the Caribbean

Earth, 65 million years ago. We all know how this story goes. A world ruled by the largest land animals to ever live is beset by a meteorite and all manner of theorised cataclysms, and a 165 million year long dynasty draws to a close. But at the same time, a new dynasty begins. Out of their hollows and burrows crawl the new heirs to the planet, our own mammal ancestors. After millions of years living in the shadow of giants, they now grow, evolve and diversify to fill the gaping void left by the dinosaurs, eventually leading to the birth of our own species, Homo sapiens.

But the first intrepid pioneers into that void looked very different to the massive whales or regal tigers of today. They were small and inconspicuous in order to survive in a world of colossal beasts. But what did they look like? What was life like for these ancient ancestors?

A Living Fossil

The answer lies in the undergrowth of the Caribbean island of Hispaniola (This island encompasses both Haiti and the Dominican Republic). An elusive creature, rarely seen by locals and tourists alike, takes refuge underground or in hollows when the sun is high. At night, however, it emerges. With its long snout, small eyes, and scaly tail, you would be forgiven for thinking it looks like a shrew. But this creature is much stranger than any shrew.

A stuffed Hispaniolan solenodon, posed to show the flexibility of the snout. Photo by belgianchocolate on Flickr

It’s a solenodon. To be exact, a Hispaniolan solenodon (Solenodon paradoxus). There is only one other living member of its genus, Solenodon cubanus, living on the island of Cuba. They are the last members of a truly ancient group.

The solenodon has existed almost unchanged for 76 million years. It diverged from the ancestors of other mammals around this time, and has a variety of strange traits that are found in no other mammal groups.

A Bizarre Beast

The Hispaniolan solenodon is an insectivore, and uses its long snout and whiskers to sense prey in the dense Caribbean undergrowth. This behaviour may seem run-of-the-mill for a small insectivore, but the Hispaniolan solenodon takes it one step further. It has a ball-socket joint in its snout, allowing for greater flexibility as it forages in tight spaces. The nocturnal, insectivorous feeding habits of the solenodon provide insight into the lifestyle of our early mammal ancestors, but this unassuming little creature has another trait that is truly primeval.

It is one of the only venomous mammals. The meaning of solenodon is “slotted tooth”, a name that refers to the unique grooves in its incisors. It uses these grooves to inject venomous saliva potent enough to paralyse small animals. Fossil records indicate that venomous saliva was common among early mammals, but most mammals lost this trait over time. Like much of the solenodon’s life history, the reason this enigmatic animal retained its venom remains a mystery.

Bringing The Past Into The Future 

It’s a mystery scientists hope to solve, but first they must make sure the solenodon is still around to be studied. After surviving the extinction event that ended the dinosaurs, the ensuing 65 million years of changing continents, changing climates and the rise and fall of countless species, the solenodon is in danger of disappearing at the hands of Earth’s new dominant life form: us. Once the apex predator of Hispaniola, deforestation and introduced species have put the Hispaniolan solenodon at risk of extinction. Thankfully, there are efforts to find out more about the solenodon in order to save the species. With luck, it will continue to forage in the undergrowth of its tropical home, reminding us all of our own humble beginnings.