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Types
Oviparous animals consist of both endotherms and ectotherms; some swim in the ocean, others walk over land, and still other oviparous animals fly. Birds are the most common mammals that undergo this development strategy. Many fish also fall under this category. Insects, as well as arachnids, develop their young oviparously. Finally, reptiles also fall under the category of oviparous egg-layers.
Advantages
A question arises pertaining to why animals perform different methods of incubation. Natural selection answers part of this question. Being oviparous and laying eggs means a distinct advantage for some animals; namely, in the form of energy. For mammals that give live births, extra energy becomes necessary, which means that excess food becomes mandatory. When eggs incubate externally, no excess food is required -- which can be extremely beneficial in locations short on food. It also doesn't require animals to go through pregnancy, which can be harsh on an animal's body.
Disadvantages
The advantages of oviparous animals might make it seem like an easy life, but it's not without drawbacks as well. Oviparous animals must still incubate their eggs constantly for proper embryonic development. Not only this, but they must ensure that predators -- which are always looking for easy food targets -- do not reach the eggs. These tasks can be difficult to perform when the animal must also gather food for itself.
Similar
Oviparous animals are defined by being internally fertilized; however, eggs undergo embryonic development starting as a zygote externally. Often mistaken for oviparous, other types of development include "ovuliparity," which means that not only does embryonic development occur externally, but so does fertilization. This can often be seen in many types of fish. "Viviparity" is the opposite of oviparity and is the process employed by the majority of mammals, including humans.