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A pregnant Southern platyfish. Pregnancy has been traditionally defined as the period of time eggs are incubated in the body after the egg-sperm union. [1] Although the term often refers to placental mammals, it has also been used in the titles of many international, peer-reviewed, scientific articles on fish.
Paraphilias are sexual interests in objects, situations, or individuals that are atypical. The American Psychiatric Association, in its Diagnostic and Statistical Manual, Fifth Edition (DSM), draws a distinction between paraphilias (which it describes as atypical sexual interests) and paraphilic disorders (which additionally require the experience of distress, impairment in functioning, and/or ...
Several groups of fish have evolved parental care. The ratio of fish genera that exhibit male-only: biparental: female-only care is 9:3:1. [40] Some fish such as pipefish, sea dragons and seahorses (Syngnathidae) have a form of male pregnancy, where the female takes no part in caring for the young once she has laid her eggs.
However, drinking more milk isn't the only solution to this. "Eating a healthy, well-balanced diet can help prevent these deficiencies," Werner says. 7. You're actively avoiding milk and it's ...
The release of eggs and sperm into the water is known as spawning. [4] In motile species, spawning females often travel to a suitable location to release their eggs. However, sessile species are less able to move to spawning locations and must release gametes locally. [4] Among vertebrates, external fertilization is most common in amphibians ...
Because the newborn fish are large compared to the fry of oviparous fish, which are those that lay eggs, newborn fish of livebearers are easier to feed than the fry of egg-laying species, such as characins and cichlids. This makes them much easier to raise, and for this reason, aquarists often recommend them for beginning fish breeder hobbyists.
A female produces an ovum with a full set (two sets of genes) provided solely by the mother. Thus, a male is not needed to provide sperm to fertilize the egg. This form of asexual reproduction is thought in some cases to be a serious threat to biodiversity for the subsequent lack of gene variation and potentially decreased fitness of the offspring.
Histotrophic (tissue eating) viviparity means embryos develop in the female's oviducts but obtain nutrients by consuming other tissues, such as ova or zygotes. [10] This has been observed primarily among sharks such as the shortfin mako and porbeagle, but is known for a few bony fish as well such as the halfbeak Nomorhamphus ebrardtii. [12]