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Cloaca of a red-tailed hawk. A cloaca (/ k l oʊ ˈ eɪ k ə / ⓘ kloh-AY-kə), pl.: cloacae (/ k l oʊ ˈ eɪ s i / kloh-AY-see or / k l oʊ ˈ eɪ k i / kloh-AY-kee), or vent, is the rear orifice that serves as the only opening for the digestive (), reproductive, and urinary tracts (if present) of many vertebrate animals.
The traditional modes of reproduction include oviparity, taken to be the ancestral condition, traditionally where either unfertilised oocytes or fertilised eggs are spawned, and viviparity traditionally including any mechanism where young are born live, or where the development of the young is supported by either parent in or on any part of their body.
While a single specific cause is unknown, chronic egg laying is believed to be triggered by hormonal imbalances influenced by a series of external factors. [1] As in the domestic chicken, female parrots are capable of producing eggs without the involvement of a male – it is a biological process that may be triggered by environmental cues such as day length (days becoming longer, indicating ...
Most Store Eggs Are From Chickens That Roam Free Though many egg cartons have labels such as "cage free," "free range," and "pasture raised," a majority of hens are kept in cages. Only around 29% ...
During co-nesting, before a bird starts laying its own eggs, it will toss out eggs laid previously by other females. [8] As a result, the last egg-layers may contribute more eggs to the common nest, [8] and this will increase the chances that newly laid eggs bearing the genetic material of that female will have a better chance of survival.
The only living mammals that lay eggs are echidnas and platypuses. In the latter, the eggs develop in utero for about 28 days, with only about 10 days of external incubation (in contrast to a chicken egg, which spends about one day in tract and 21 days externally). [11] After laying her eggs, the female curls around them.
Vent sexing, also known simply as venting, involves squeezing the feces out of the chick, which opens up the chick's anal vent (called a cloaca) slightly, allowing the chicken sexer to see if the chick has a small "bump", which would indicate that the chick is a male. Some females also have bumps, though they are rarely as large as those of ...
During breeding season, they use it when depositing eggs in the mantle cavity of freshwater mussels, where their eggs develop in reasonable security. Seahorses have an ovipositor for introducing eggs into the brood pouch of the male, who carries them until it is time to release the fry into a suitable situation in the open water.