Why some hedgehogs have no spines: Meet the gymnure

When most people think of a hedgehog, they picture a small, round animal covered in sharp spines, curling into a ball at the first sign of danger. But not all members of the hedgehog family fit this image. Within the same family, Erinaceidae, lives a fascinating group of animals that lack spines altogether: the gymnures, also known as hairy hedgehogs.

Family Ties: Hedgehogs and Gymnures

Hedgehogs (subfamily Erinaceinae) and gymnures (subfamily Galericinae) share a common ancestor, but they followed different evolutionary paths. Hedgehogs developed their iconic coat of modified hairs (stiffened into spines) as a defence mechanism. Gymnures, on the other hand, retained a coat of coarse fur instead of evolving spines.

Despite their different appearances, both groups belong to the same family. This makes gymnures close relatives of hedgehogs, even though they look more like large shrews or rats to the untrained eye.

Why No Spines?

The absence of spines in gymnures is the result of different evolutionary pressures. Hedgehogs evolved in open habitats where curling into a spiky ball offered protection against predators. Gymnures, however, inhabit dense forests and undergrowth in Southeast Asia, where stealth and speed are better survival strategies than armour.

Instead of relying on spines, gymnures use:

• Camouflage and concealment in leaf litter and undergrowth.
• Agility, moving quickly through dense vegetation.
• Strong odour secretions from scent glands, which deter some predators.

Evolution is always about trade-offs. In environments where hiding and fleeing worked better than standing still with spines, gymnures thrived without developing the hedgehog’s trademark armour.

What Gymnures Look Like

At first glance, a gymnure can be mistaken for a large rodent. They have elongated snouts, sharp teeth, small ears, and a tail that can be quite prominent compared to the almost invisible tails of hedgehogs. Their fur is coarse, often grey or brown, sometimes with lighter or darker patches depending on the species.

Some species can reach the size of a small rabbit, making them larger than most hedgehogs. The absence of spines and their longer body shape make them appear less “cute” to human eyes, which may explain why they are not as well-known or popular in captivity.

Behaviour and Ecology

Gymnures are primarily nocturnal, like hedgehogs, and they are also insectivores, feeding on insects, worms, small vertebrates, and fruit. They are solitary, maintaining territories marked with scent.

Unlike hedgehogs, gymnures do not curl into a ball when threatened. Instead, they hiss, bite, or release a musky odour. Their reliance on smell as a defence mechanism is so strong that some species have earned nicknames like “moon rats” due to their pungent scent.

They are found mainly in Southeast Asia, from southern China to the Malay Peninsula, often in moist tropical forests. Their survival depends heavily on intact forest habitats, which makes them vulnerable to deforestation and human encroachment.

Why They Matter

Although less famous than their spiny relatives, gymnures play an important ecological role. As opportunistic insectivores and omnivores, they help regulate insect populations and act as scavengers in their ecosystems. Studying gymnures also gives scientists valuable insights into the evolution of hedgehogs. By comparing these two subfamilies, researchers can better understand how spines evolved as a defence strategy and why some lineages never developed them.

In Summary

Not all hedgehog relatives are spiny. Gymnures, the “hairy hedgehogs,” traded spines for fur, stealth, and a strong scent. Living in dense Asian forests, they show us that survival comes in many forms. Where hedgehogs depend on armour, gymnures depend on speed and secrecy, two very different answers to the same evolutionary question: how to stay alive when you are small and vulnerable.