How Do Porcupines Mate and Reproduce? A Detailed Analysis of the Reproductive Process
Porcupines can be roughly divided into two types, Old World and New World, and they have completely different ecological environments and social structures. New World porcupines include the well-studied North American porcupine (Erethizon dorsatum), which lives in trees and feeds on leaves, fruits and bark. Old World porcupines live on the ground (in places like burrows), and their food is fruits, roots and bulbs. Then there is social structure: New World porcupines are generally social animals, while Old World porcupines live in family units.
The mating systems of these two kinds of porcupines are also very different. The Old World porcupine is one of the few monogamous animals on Earth; a pair of adult porcupines will stay together for life and breed several times a year (giving birth after about 90 days of pregnancy).
The female North American porcupine, by contrast, mates only once a year, for 8—12 hours (and generally rarely mates with other New World porcupines). In fact, their “frigidity” is not something they can decide for themselves, because their vaginas are often sealed by a membrane. Only in September does the membrane of their vagina dissolve and begin to secrete a foul-smelling mucus, and the males come following the scent. But when the first male reaches her habitat, she is actually not yet ready to ovulate, so the first one just waits beside her for her to be ready——at the same time creating ample time and opportunity for other male North American porcupines that come following the scent. As a result, the males that find the same female launch a great battle, fought so fiercely that they end up with scars, missing ears and various other degrees of external injuries.
The male that wins the defense will sit on a branch slightly lower than the female to guard her, which ensures that other males can be kept from approaching. When the female's ovulation period arrives, the male will urinate on her to stimulate the hormones in her body and bring her into estrus, and only then does mating formally begin.
However, the urine here is not like human urine, but rather urination similar to ejaculation, a high-speed launching method that shoots urine from one branch onto another.
If the female is unwilling to mate with him, she will scream at him, shake off the urine on her body and then turn and run far away, but she may also behave unkindly, such as biting him, sweeping him with her tail and so on. The male must respect the female's wishes, because she has measures to prevent herself from being raped.
When the female accepts this partner, she will slightly raise her hind legs and lift her tail up onto her back to prevent the spines on her tail from injuring the male. The spines on her body are no longer held straight up; she makes the spines on the other parts of her body lie flat, making it easier for the male to climb onto her without being injured. When they have mated several times and the female feels she can conceive, she will take the initiative to leave the male, and the male quickly leaves to look for the next target. The impregnated female remains pregnant for the next seven months, and after giving birth she spends several months caring for the newborn before starting another round of mating and reproduction.
Interestingly, the Old World porcupine can mate again immediately after the female gives birth, though at this time the female will not be at risk of becoming pregnant; perhaps it is precisely because of this that their monogamous family pattern can continue intact.