Solenodon

Lore & Background

Solenodons are found only on the islands of Cuba and Hispaniola. The Cuban solenodon is generally smaller and rusty brown with black on its throat and back, while the Hispaniolan solenodon is darker brown with a yellowish tint to the face. Both species have extremely elongated cartilaginous snouts, long naked scaly tails, hairless feet, and small eyes. The Hispaniolan solenodon's snout has a ball-and-socket joint at the base for increased mobility, allowing it to investigate narrow crevices for prey.

Solenodons are among a handful of venomous mammals. They produce venom in enlarged submaxillary glands and inject it through grooves on their second lower incisors. The venom contains kallikreins (KLK1), serine proteases that prevent blood clotting, cause hypotension, and are fatal to prey. Symptoms of a bite include general depression, breathing difficulty, paralysis, and convulsions. Their diet consists largely of insects, earthworms, and other invertebrates, but they also eat vertebrate carrion, fruits, roots, and vegetables.

Reproduction is slow: females produce only two litters of one or two pups per year. Young cling to the mother's two teats, which are placed toward the back of the animal. The nursing period lasts about seventy-five days. Solenodons are solitary as adults and rarely interact except to breed. They generate clicking noises for echolocation, helping them navigate and find food despite poor vision.

Reader's Guide

Solenodons hold significant evolutionary importance as one of the oldest lineages of living mammals. Genetic analysis confirmed in 2016 that they belong to an evolutionary branch that split from the lineage leading to hedgehogs, moles, and shrews before the Cretaceous-Paleogene extinction event, diverging from other living mammals about 73 million years ago. Their venom delivery system, shared with only a few other mammals, may represent a primitive mammalian characteristic lost in most modern groups. Both extant species face threats from habitat destruction and predation by non-native cats, dogs, and mongooses introduced by humans. The Cuban solenodon is considered Endangered; it was thought extinct until a live specimen was found in 2003. The Hispaniolan solenodon was also once thought extinct due to its secretive behavior, but recent studies show it is widely distributed across Hispaniola, though it does not tolerate habitat degradation. The two extinct species—the giant solenodon and Marcano's solenodon—likely disappeared within the last 500 years due to predation by introduced rats.

Did You Know?

• The name 'solenodon' derives from Ancient Greek for 'grooved tooth,' referring to the grooves on their lower incisors through which venom flows.
• Solenodons are one of only two families of Caribbean soricomorphs; the other family, Nesophontidae, became extinct during the Holocene.
• The venom of solenodons contains kallikreins (KLK1) similar to serine proteases found in venomous snakes like vipers, having evolved in parallel from an ancient toxin precursor.
• Female solenodons have two teats positioned almost on the buttocks, and young follow the mother by hanging onto these elongated teats.

Evolutionary Legacy and the Living Fossil

The solenodon stands as one of the most remarkable survivors in the mammalian world. Genetic analysis confirmed in 2016 that this tiny burrower belongs to an evolutionary branch that split from the lineage giving rise to hedgehogs, moles, and shrews before the Cretaceous-Paleogene extinction event wiped out the dinosaurs. Estimates place the divergence of solenodons from other living mammals at roughly 73 million years ago, making them one of only two families of Caribbean soricomorphs still in existence. Their closest relative, the Nesophontidae family, went extinct during the Holocene, with molecular data suggesting that split occurred around 57 million years ago. The animal's origins remain partly obscure, though Oligocene North American genera like Apternodus have been proposed as distant relatives. Two additional species—the giant solenodon and Marcano's solenodon—vanished within the last five hundred years, likely felled by introduced rats. Because the solenodon has persisted virtually unchanged across this staggering span, it is frequently labeled a living fossil, a creature carrying ancient mammalian traits into the modern era.

The Venomous Bite

Perhaps no feature of the solenodon is more striking than its venom delivery system, which gives the animal its very name from the Greek words for channel and tooth. Modified salivary glands in the lower jaw pump venom through grooves carved into the second lower incisors, making the solenodon one of only a handful of venomous mammals on Earth. Early research compared the saliva to snake neurotoxins, but more recent work revealed the venom is closely related to that of the northern short-tailed shrew and is composed primarily of kallikreins—specifically KLK1, a serine protease that disrupts blood clotting, triggers hypotension, and can prove lethal. Remarkably, this KLK1 protein has evolved in parallel with the serine proteases found in viper venom, both tracing back to an ancient toxin precursor. The venom is produced in enlarged submaxillary glands and delivered exclusively through the lower teeth. A bite can cause depression, breathing difficulty, paralysis, and convulsions, with sufficient doses killing laboratory mice. Fossil evidence suggests this dental venom mechanism was once a broader ancient mammalian trait, now retained only in a couple of very old lineages.

Anatomy and Foraging Behavior

The solenodon's body is a study in specialized, ancient design. Resembling an oversized shrew, it ranges from 28 to 32 centimeters nose to rump and weighs between 0.7 and 1.0 kilograms. Its most distinctive feature is the extremely elongated, flexible cartilaginous snout; in the Hispaniolan species, a ball-and-socket joint at the base grants extra mobility for probing narrow crevices where prey hides. Other oddities include hairless, scaly feet, a long naked tail, tiny eyes, and two teats positioned almost on the female's buttocks. The animal also secretes a musky, goat-like odor from glands in its inguinal and groin regions. Foraging is a methodical affair: the solenodon sniffs the ground, uses sharp claws to breach physical barriers, and when prey is found, raises its forelimbs to either side before thrusting its head forward to seize the animal with an open jaw. Diet centers on insects, earthworms, and invertebrates, though carrion, small reptiles, amphibians, fruits, and roots also appear. Captive observations revealed sex-based foraging differences—females scatter food to ensure nothing is missed, while males lap with their tongue and use the lower jaw as a scoop.

A Fragile Caribbean Existence

Both living solenodon species are confined to the Caribbean: the Cuban solenodon on Cuba and the Hispaniolan solenodon across Hispaniola, where it occupies habitats from lowland dry forest to highland pine woodland. Their isolation makes them acutely vulnerable. Habitat destruction steadily erodes the already limited land available to them, while non-native predators—cats, dogs, and mongooses—introduced by humans to control snakes and rodents have become serious threats. The two now-extinct species, the giant solenodon and Marcano's solenodon, are believed to have perished within the last five hundred years, presumably driven to extinction by introduced rats. West Indian peoples have long recognized the danger of a solenodon bite, and the animal's nocturnal, burrowing lifestyle keeps it largely hidden from casual observation. In captivity, Cuban individuals have lived up to five years and Hispaniolan ones up to eleven, though wild lifespans remain unknown. With only two species remaining on two island groups, the solenodon's future hinges on protecting the small, fragmented habitats that are all that separate it from the fate of its extinct relatives.