User:Beccyw/Maternal behavior in vertebrates

Article Draft
Plans for improvement:


 * Move the "Brood Parasitism" section out of the bird heading and make it its own heading, then expand on it by adding more information about brood parasitism in birds and add information about brood parasitism in fish
 * Add a section about maternal care in amphibians
 * Add a section about maternal care in fish
 * Add photos to help with comprehension of the article as there are none at all right now
 * Edit the introductory sentence and lead section to be more specifically about maternal care
 * Baby Reindeer Scratching its Head (14130501937).jpgs to add to unedited sections of main article are next to the lead

Lead
Maternal behavior is a form of parental care that is specifically given to young animals by their mother in order to ensure the survival of the young. Parental care is a form of altruism, which means that the behaviors involved often require a sacrifice that could put their own survival at risk. This encompasses behaviors that aid in the evolutionary success of the offspring and parental investment, which is a measure of expenditure (time, energy, etc.) exerted by the parent in an attempt to provide evolutionary benefits to the offspring. Therefore, it is a measure of the benefits versus costs of engaging in the parental behaviors. Behaviors commonly exhibited by the maternal parent include feeding, either by lactating or gathering food, grooming young, and keeping the young warm. Another important aspect of parental care is whether the care is provided to the offspring by each parent in a relatively equal manner, or whether it is provided predominantly or entirely by one parent. There are several species that exhibit biparental care, where behaviors and/or investment in the offspring is divided equally amongst the parents. However, even in species who exhibit biparental care, the maternal role is essential since the females are responsible for the incubation and/or delivery of the young.

Fish
The majority of fish are oviparous, though there are many that are ovoviviparous and viviparous.

Oviparous fish
Many oviparous fish display no maternal behaviors aside from laying the eggs, but some mothers will stay with their clutch to defend the eggs and fry from predators, a behavior very common among cichlids. Many cichlid species, such as Cichla ocellaris, will also remove underdeveloped eggs from the clutch, a behavior performed by both parents. Many female cichlids also fan their eggs with their fins, especially in slower moving water, in order to increase oxygenation and get rid of build up of undesired materials around the eggs.

Mouthbrooding
A lot of cichlid species carry their eggs and young in their mouth for an extended period of time while they hatch and grow. This behavior is most often displayed by the mother, though there are some species where both parents or just the father mouthbrood. In maternal mouthbrooders after the eggs are laid the mother scoops them into her mouth and keeps them there, sometimes for multiple weeks, during which she will not eat and will put all her energy into caring for her young.

Ovoviviparous and viviparous fish
In both ovoviviparous and viviparous fish the female incubates her young inside her body before giving birth to live young, the major difference is where the young get their nutrition during incubation. Ovoviviparous fish embryos mostly get their nutrients from the yolk of their eggs while viviparous fish embryos mostly get their nutrients directly from their mother. The gestation period is usually the only maternal care provided in these fish as they are developed when they are born.

Amphibians
Most Amphibians are oviparous and lay their eggs in water, though some have adapted to lay them on land. There are also some species that are viviparous, giving birth to live young. Eggs can be fertilized either internally or externally depending on the species. Many amphibians exhibit maternal behaviors such as egg and young brooding and transport, as well as varying methods of feeding their young.

Frogs
Frogs have developed many different maternal behaviors across varying species. The most common maternal behavior among frogs is egg attendance, wherein the mother will remain near her eggs as they develop to protect them from predators. A mother may also stay with her clutch in order to prevent desiccation, as she can rehydrate them via ventral brooding. Some species have also been observed oxygenating their eggs by moving them around occasionally. Frogs of the genus Hemiphractus carry their eggs around on their back until they hatch. Some species of this genus develop a dorsal pouch to carry their young inside while other leave them exposed. Some frogs, such as poison dart frogs, will lay unfertilized eggs for her clutch to eat.

Caecilians
Caecilians can reproduce either by oviparity or viviparity, with some young having an aquatic larval stage while some develop to live on land immediately. Oviparous females build nests on land and keep their clutch there until they hatch, regardless of if they have an aquatic stage or not. Once young with an aquatic stage hatch they are able to survive on their own in the water without any more maternal care, however other young are altricial when they hatch, and rely on their mother to look after them until they develop enough to live fully on land. The mother feeds these altricial young by a process known as maternal dermatophagy, in which she will feed pieces of her skin to her young. Viviparous caecilians also give birth to altricial young. These young may be fed by maternal dermatophagy in the same way that oviparous species are fed, or they may be fed by a more specialized version in which the young eat their mother's hypertrophied oviduct or drink from her cloacal opening.

Brood parasitism
Brood parasitism is a reproductive strategy exhibited in some birds and one species of fish, wherein a parasite will lay their eggs in the nest or clutch of a host who will provide care for the invasive young.

Brood parasitism in birds
The parasitic birds have evolved ways to ensure the success of their offspring by having it be raised by a host, allowing them to no longer have to invest energy into maternal care themselves. As a result, their offspring receive maternal care from a host bird, which can cause their natural maternal behaviors to be affected. This results in them often neglecting to care for their own offspring. Although this behavior can be performed occasionally by many different birds, only about 1% of all bird species worldwide are considered to be obligate brood parasites.

Brood parasitism in fish
The only vertebrate species to practice brood parasitism other than birds is the cuckoo catfish. These fish prey specifically on mouthbrooding cichlids. When the female cichlid lays her eggs on the ground the cuckoo catfish will lay her eggs among the clutch and a male will fertilize them before the cichlid picks her eggs up in her mouth, causing her to also pick up the cuckoo catfish's eggs. The cuckoo catfish eggs hatch before the cichlid eggs and the cuckoo catfish is able to eat the cichlid eggs and reside within the protection of the cichlid's mouth until they are spit out.