10 Surprising Facts About Hamsters

Did you know that some hamsters can inflate their cheeks to swim? Learn more about these adorable mammals.

European hamster with black tummy standing upright in grass

Stefan Huwiler / Getty Images

Hamsters are cute, furry mammals with oversized cheek pouches and short tails. These small rodents live in the wild, and some species are popular as house pets. There are about 20 hamster species found in a variety of habits, from deserts and plains to sand dunes and agricultural fields across Europe, Asia, and Northern Africa. One species, the European hamster, is critically endangered.

From their elaborate burrows to their continuously growing incisors, there’s much to learn about these little balls of fluff. Here are a few things you may not know about hamsters.

Fast Facts

  • Common Name: Hamster
  • Scientific NameCricetinae
  • Average Lifespan in the Wild: 2 to 3 years
  • Average Lifespan in Captivity: 2 to 4 years
  • IUCN Red List Status: Least concern to critically endangered, depending on the species
  • Current Population: Unknown

1. There Are About 20 Species of Hamsters

Hamster with gold fur crawling onto a green leaf

vadimrysev / Getty Images

Hamsters belong to the family Cricetidae, which includes voles and lemmings as well as rats and mice. The 20 or more species of hamsters are quite varied. Some are ratlike, like the seven members of the Cricetulus genus, while the lone member of the Cricetus genus, the European or common hamster, has unique black fur on its belly.

The most popular species for pets are the golden or Syrian hamster (Mesocricetus auratus), and three different members of dwarf hamsters: the winter white dwarf hamster (Phodopus sungorus), Campbell's dwarf hamster (Phodopus campbelli), and the Roborovski hamster (Phodopus roborovskii), the smallest of all hamster species.

2. They Are Nocturnal Creatures

Being prey for so many animals, it’s no wonder that most hamsters are nocturnal. They spend their days hiding from snakes, eagles, foxes, badgers, and other carnivores. In the wild, hamsters dig burrows with deep tunnels and multiple entrances for protection and to sleep during bouts of torpor. They are solitary animals, spending most of their time in their burrows alone. They are also fiercely territorial and will attack any invading hamsters that dare venture near.

3. They Are Promiscuous

Male and female hamsters are polygynandrous—meaning they have multiple mates. During breeding season, males travel from burrow to burrow and mate with any female they find, provided said female hasn't already mated. Once she has mated, a copulatory plug forms on the female to prevent any further insemination. Hamsters are territorial, and females frequently kick the male out after mating.

Females will normally birth two to four litters a year—their gestation period is only 15 to 22 days—and litter sizes can range from one to 13 young, though the average is around five to seven.

4. Hamsters Are Banned in Hawaii

Given their high reproductive rate and the fact that Hawaii’s climate is similar to the hamsters' native habitat, these critters are illegal in Hawaii. Hamsters could quickly establish large colonies in the state if they ever escaped into the wild, which would pose a problem for agriculture and other native species.

Hawaii’s list of banned animals also includes hummingbirds, snakes, gerbils, hermit crabs, and salamanders.

5. Their Teeth Never Stop Growing

Like all rodents, hamsters’ incisor teeth have no roots and never stop growing. By gnawing, they keep their teeth nice and sharp while also preventing them from becoming too overgrown.

Researchers studying rodents’ teeth have discovered that their incisor teeth contain active stem cells. This factor, coupled with rodents’ trait of constantly regrowing their teeth, gives scientists hope of one day replicating the tooth regeneration process in humans.

6. They Hoard Food

Hamster filling its cheeks with rosehips
Michaela Walch / Getty Images

Hamsters are built for food storage. Their cheeks are like tiny totes that they can fill with fruit, grains, roots, and leaves—up to an amount that's equivalent to their own bodyweight. When they find an abundant source of food, they fill those cheek pouches and return to their burrows, where they have prepared food chambers for storage. In fact, their name comes from the German word "hamstern", which means to forage.

But their cheeks also have a secondary purpose: They fill up with air so that hamsters can float in water.

7. They Are Prone to Bacteria and Viruses

Hamsters carry salmonella and, while rare, they are also prone to Lymphocytic choriomeningitis, a virus that can result in flulike symptoms. The primary methods of zoonotic disease transfer from hamsters and other rodents to humans is through bites, direct contact with the animal, and indirect contact with contaminated objects. Young children and pregnant adults are particularly at risk of contracting it.

8. Some Hibernate (Sort of)

While most hamsters do not hibernate during cold weather, one species called the golden hamster (aka the Syrian hamster, commonly kept as a pet) stays in its burrow, blocks the entrance with soil, and sleeps in a grass-lined nest, waking once per week to eat food it has stashed. Apparently, while hibernating, its heart drops from the usual 400 beats per minute to just four, and it only takes two breaths per minute.

9. They Have Poor Eyesight

Most hamsters are nearly blind in bright light. It does much better at seeing in dim light, which is why it's a nocturnal animal. Even so, it can't see much past the tip of its own nose. Because of this, a hamster relies on other senses to navigate during the daytime, such as its super-sensitive whiskers and scent glands on its back that leave traces to guide it back home.

10. European Hamsters Are Critically Endangered

Wild hamster with black belly on hind legs in dirt

Miroslav Hlavko / Getty Images

Once widespread throughout Europe, the black-bellied, European, or common hamster is critically endangered. The only member of the Cricetus genus, this hamster's range and population have both declined significantly throughout western, central, and eastern Europe, no longer inhabiting an estimated 75% of its native range. Changes in agricultural practices, commercial and residential development, pollution, and climate change are the biggest threats to these small animals.

Though conservation, monitoring, and reintroduction measures in parts of the hamsters’ range have been successful, the European hamsters’ decline has occurred rapidly. Plans for conservation throughout all countries where they occur are needed to prevent extinction.

Save the European Hamster

  • Support initiatives that require E.U. Member States to take measures toward favorable conservation of the species in Europe.
  • Support diversified farming practices that offer food and vegetative cover for the hamsters.
  • Support modifications to infrastructure and private development projects where the hamsters are present.
Frequently Asked Questions
  • How smart are hamsters?

    In past studies, wild hamsters have exhibited great spatial intelligence (including a visual memory) while foraging for food. Many believe they can also learn their names and bond with their human companions.

  • Why do hamsters eat their own poop?

    Hamsters are coprophagic. They eat their own poop to make sure they're absorbing all nutrients from the foods they've eaten. The kind of feces they eat is soft—sometimes called "night feces"—and they often eat it directly from the anus.

  • Do hamsters eat their babies?

    Hamsters do, on occasion, kill and eat their babies if they're feeling too stressed to rear them. This is more common among first-time mothers.

  • Can you let a hamster go in the wild?

    Never let a pet hamster or any domestic animal go in the wild for their sake and the environment's. Domestic animals are not accustomed to hunting for their food, so they risk starving or dying by dehydration. On top of that, they could be invasive.

Why Pets Matter to Treehugger

At Treehugger, we are advocates of animal welfare, including our pets and other domestic animals. The better we understand our cats, the better we can support and protect their wellbeing. We hope our readers will adopt rescue pets instead of shopping from breeders or pet stores, and will also consider supporting local animal shelters.

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