Search results
Results from the WOW.Com Content Network
Some females abort or resorb their own young while they are still in development after a new male takes over; this is known as the Bruce effect. [31] This may prevent their young from being killed after birth, saving the mother wasted time and energy. However, this strategy also benefits the new male.
In animals, the process involves a sperm fusing with an ovum, which eventually leads to the development of an embryo. Depending on the animal species, the process can occur within the body of the female in internal fertilization, or outside in the case of external fertilization. The fertilized egg cell is known as the zygote. [2] [5]
The Bruce effect, or pregnancy block, [1] [2] is the tendency for female rodents to terminate their pregnancies following exposure to the scent of an unfamiliar male. [3] The effect was first noted in 1959 by Hilda M. Bruce, [4] and has primarily been studied in laboratory mice (Mus musculus). [1]
Some rodent species (most typically males) will take the chance to kill neonates that are unrelated to them should opportunity permit. There is thought to be several benefits by doing so, which not only include nutrition benefits (particularly where food is in short supply [8]) but also non-direct benefits, such as allowing access to more resources, improving reproductive opportunities and the ...
Human babies are unique in the animal kingdom due to their large head size relative to their bodies. This has an effect on the birthing process for humans as the bipedal gait of a human causes the birthing canal to be relatively narrow and twisted in the middle.
A boa constrictor in the U.K. gave birth to 14 babies — without a mate. The process is called parthenogenesis, from the Greek words for “virgin” and “birth.” It tends to occur in ...
For most species, the amount a fetus grows before birth determines the length of the gestation period. Smaller species normally have a shorter gestation period than larger animals. [2] For example, a cat's gestation normally takes 58–65 days while an elephant's takes nearly 2 years (21 months). [3]
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!