Explore more: Reproduction in Animals Female platypus can lay two eggs at a time while an echidna can lay only one egg at a time. New Mexico Whiptail . The reason that some animals lay eggs is because that is more beneficial to them than than it is to give birth to a live offspring. They are all females that lay eggs that hatch without being fertilized by a male. Frogs are egg-laying amphibians which have soft gelatinous eggs requiring constant hydration. There are many other differences in their body structure, feeding habits, diet and so on. All birds lay eggs with a typical hard calcium shell. Student will communicate newly-obtained information in the form of a report, outline, sentences, pictures, (however you want them to display it) Student will give an oral presentation to the class. The answer is yes, hens in captivity lay eggs every day. The Duck-billed platypus. Most mammals, like humans and dogs, have a live birth. Animals which reproduce by giving birth to their young ones are called viviparous animals. Beside egg-laying, monotremes possess other traits that separate them from other mammals. Instead, it depends on the hen’s hormonal cycle. Most vipers are ovoviviparous, and all of them are deadly poisonous with just a single bite. Mammals like cat, dog and man are viviparous animals. Except for some species of snakes, all other reptiles are oviparous. These animals do not lay eggs. A female platypus lays eggs in the special holes or burrows while a female echidna, on the other hand, lays egg in her pouch. In mammals, Echidna and platypus are egg-laying. New Mexico whiptails are indigenous to Chihuahua (Mexico), Arizona, and New Mexico. Usually, animals that are in the same class have babies in the same way: by laying eggs or through live birth. Generally, vipers are the snakes that don’t lay eggs, only a few like Psedocerastes, Cerastes, and Echis species are oviparous. Either way, the farm chicken you see today is basically the outcome of genetic selection throughout history. Egg-laying mammals belong to a group called monotremes. Egg laying is common to all species of birds and most reptiles, though several species of snakes and lizards are viviparous. New Mexico whiptail is one of the numerous lizards which can reproduce via parthenogenesis. Birds, insects, reptiles and fishes are oviparous animals. Student will gather research information on egg-laying animals. However, laying eggs doesn’t dependent on the rooster’s presences. Indo-Pacific geckos are parthenogenic animals. Most fish and amphibians are oviparous as well. There are about 224 species of Vipers in the world, and only some of them lay eggs. Eggs are pretty small. There are exceptions to every rule, some reptiles and fish bear live young, and some mammals lay eggs. Almost all fishes are oviparous. All birds and one mammal. Pages in category "Creatures that lay eggs" The following 76 pages are in this category, out of 76 total. Among mammals, only the platypus and four species of echidna lay eggs. Student will work with a group to create model eggs and model habitat. Animals which reproduce by laying eggs are called oviparous animals. Other classes lay eggs. They do not have teats to nurse their young.