Is it a boy or a girl?

Often we find the sex of a pet when they present us with a new family!

The best way to learn whether your pet is a male or female is to take a visual lesson from an experienced pet shop owner, breeder or veterinarian. Following are some of the visual cues these experienced folks look for in each species.

Gerbils, Hamsters, Rats, and Mice:

  • Hold your pet in your hand “belly up." The space between the anus and the genital area is greater in the male than in the female. In addition, the genital opening is usually more prominent and rounded in the male rodent.
  • If you suspect your pet is a male, you can try gently applying some pressure to his stomach. This will force the testicles into the scrotum thus making them more visual. Another sign of a male gerbil is a dark, pigmented scrotum.
  • In hamsters, take a look from above – males have a larger, more rounded posterior because of the presence of fat pads that keep the testicles in the scrotum. Female hamsters have a more flat, sleek rear end that comes to a point at the base of the tail.


  • Your best bet is to ask your veterinarian or an experienced handler. The testicles of a male rabbit can sometimes elude even the most experienced hand.


  • Spontaneous ovulators: All small rodents are polyestrus and spontaneous ovulators, which means females come into heat often and do not need male stimulation to ovulate (release eggs). Breeding comes easy to these small animals and reproductive problems are uncommon.
  • Induced ovulators: Rabbits, however, fall outside of this category. Female rabbits are induced ovulators, like cats and ferrets, which means they do not release eggs until they breed with a male. In nature, a rabbit’s breeding season is influenced by daylight (length of day) and temperature. In the northern hemisphere, rabbits are more receptive to mating in the spring than in the fall, but in controlled environments, male rabbits will mate at any time.

Random Reproductive Facts:

  • Once gerbils breed, they are monogamous for life. In fact, an older gerbil that has lost its mate usually will not accept a new spouse.
  • Female mice housed together without a male will not have an estrus cycle. But, add a male and the females will come into heat within four days.
  • Mature, adult female hamsters caged together may fight to the point of fatally wounding each other.
  • Cannibalism among hamsters is not uncommon. A mother may cannibalize her young and adult hamsters may even attempt to cannibalize each other. Handling of the young by a human is a potential cause for cannibalism, so it is best to leave mother and baby alone for as long as possible.
  • Baby guinea pigs have the appearance of being just a smaller version of the adult from day one. In fact, they are born fully furred and are able to eat soft foods after 24 hours.
  • Unlike other female rodents, guinea pig females have only one set of mammary glands.

You should consult an established breeder or veterinarian if you have specific questions about your small animal’s reproduction. There are also many good books and websites for your pet’s specific species and breed.