|
Did you know?
|
|
- In rodents, a successful pregnancy can be terminated if an alien male (one that did not cause the pregnancy) shows up and hangs out with the pregnant female. This is known as the Bruce Effect.
- Oysters can change from one gender to another and back again.
- When comparing the size of birds eggs to that of the bird that produces them, ostrich eggs are amongst the smallest and humming bird eggs are the largest.
- The female Egyptian Spiny mouse acts as a midwife to other females. She bites through the umbilical cord and licks the neonates while the mother continues to deliver the litter.
- The alpine black salamander has the longest gestation period known, which interestingly depends on the altitude. When they live at 4,600 feet above sea level, it takes over three years for an infant to develop within its mother.
- Some species of animals have delayed fertilization. This is a process whereby the male inseminates the female and spermatozoa remain viable in the female tract for some constant period of time. Sperm are stored in special utero-vaginal glands; eg: some bats mate in the autumn before hibernation but the female does not ovulate until spring. The sperm are stored in her tract intact till the time of fertilization. The fertilizing lifespan of bat sperm in the female reproductive tract is reported to range from 68-198 days depending on the species of bat. In some species of snakes it can be up to 6 years.
- Female elephants have a uniquely long oestrous cycle (16 weeks) and a gestation period of 22 months.
|
 | | |
|
|
|
