Web Documents



Anonymous E 2012

Created By: Denim Wilson
Font: small Large
  1. http://www.ehow.com/about_4567603_dolphins-reproduction-cycle.html


    Function
    [1]To begin mating, the male dolphin will rub the rear of the female with its sex organ for several minutes, after which the pair engages in what might be called a "standard" mammalian courtship. Pregnancy lasts for 11 to 12 months, depending on the species of dolphin, although all are born tail-first. Dolphins reach sexual maturity at various ages, depending on the region. Females reach this point around 7 to 12 years of age, and males at around 10 to 15 years old. Dolphins don't mate for life, and they typically give birth every 4 to 5 years until their death.

    Significance
    Dolphins are remarkable not only in their birth but also in how much they resemble humans in the process. While dolphins have sex for fun, like humans, they also give birth in an unusually human manner: they have a midwife, a female dolphin that actually assists with the birth. After birth, the newborn is sometimes assisted to the surface to take its first breath.

    Risk Factors
    Giving birth at sea is fraught with danger. Whereas human births are generally done in private, dolphins must give birth while keeping a watchful eye for predators for anywhere from 1 to 3 hours (on average). One of the dolphin's primary enemies, the shark, will inevitably zero in on a female giving birth; it can smell the blood a mile away. A pod of dolphins will form a circle around the new mother to ward off attacks until the birth is complete.

    Misconceptions
    People often forget that dolphins are mammals--an animal, like humans, who have mammalian glands. When a dolphin is born, one of its first acts is to feed from the sacs of milk located on the underbelly of the mother. Nursing underwater, however, requires some quick work: baby dolphins are actually forced to feed as quickly as possible, just so they can surface and take a breath! And because dolphins can't actually latch onto the mother, like human infants, female dolphins have evolved to squirt the milk directly into the baby's mouth.

    Expert Insight
    [2]Research into dolphin reproduction has also provided several surprising discoveries. Male dolphins are known to engage with each other sexually, and they are credited with having strong homosocial bonds. Bottlenose dolphins--the most extensively studied dolphin species--have been found to trail females for weeks, until they become sexually receptive. But unsettlingly, bottlenose dolphins have also been shown to engage in "coercive sex" with unwilling females.

Category: Spring Research Sources | Comments: 0 | Rate:
0 Votes
You have rated this item.