Dinosauria - Dinosaur Families

Egg Makers

The reproductive means of most dinosaurs is as yet unknown. mating is based on evidence from modern crocodiles. If dinosaurs were present-day lizards and crocociles, then two ovaries made eggs that passed through the funnel-shaped ostiom and into the tubular oviduct. The male Protoceratops' sperm travelled up the female's oviduct to fertilize the just-released eggs. then the eggs were "shelled" by special glands in the oviduct lining as they moved toward the cloaca, the opening of the reprodictuve tubes.

What Were Dinosaur Eggs Like?

We know that dinosaur mothers laid hard-shelled eggs, like most modern reptiles. They had course, bumpy surfaces. The amphibians, from which they evolved, had to lay their soft, jelly-covered eggs in water, where they hatched into tadpoles. Reptiles, however, can lay their eggs on land because of their toughness. Some dinosaurs laid them in hollowed-out nests in the ground. It was a great step forward to life on land.

These eggs were never very huge. If they were in proportion to the size of some adult dinosaurs, the shells would have been far too think to hatch, and wouldn't allow enough oxygen to reach the babies growing inside.

The developing baby fed its yolk in a private pod surrounded by three membranes. From the inside out, they are: the amnion, allantois, and chorioun.

Did Any Dinosaur Give Birth Instead Of Laying Eggs?

Live birth might have been possible for certain dinosaurs, such as the wide-hipped Apatosaurus. After all, not all reptiles lay eggs. Many including garter snakes, rattle snakes, and some chameleons, give birth to live young.

Did Dinosaurs Look After Their Young?

Baby hypsliophonts had strong, fully formed joints and bones. They didn't stay in their nests long enough to trample anything. This is why their eggshells are found today in one piece with just a hole in the top where the hatchlings popped out and went.

In most cases, tiny skeletons of dinosaur hatchlings have been found inside the eggs. This tells us that baby dinosaurs, like baby birds, would instinctively stay in their nest, no matter what happened to theit mother. Some were helpless as newly-hatched sparrows. Others could run around as soon as they were out of the egg, like chicken can. Parasaur

Colonies of duckbilled dinosaur nests, which had raised rims, have been found containing hatchling skeletons. The baby's teeth were worn, indicating that the mother dinosaur must have brought back food to the nest. Duckling hatchlings had poorly formed joints and bones, and their nests were full of trampled eggshells - proof that they spent a lot of time in them.

Most crocodiles and some birds lay eggs in similar kinds of bowl-shaped nests. They cover them with sand and plants. As the plants rot they give off heat, which incubates the eggs. They did not cover them completely, though. The eggs contained so many tiny pores that if they had been exposed to air, they would have dried up inside. Protoceratops

Protoceratop mothers lay their eggs in a circle in the same nest, which contains up to 30 eggs. They would then have covered them with dirt or sand to protect them until they hatched. Fossil of baby, juvenile, and adult Protoceratops have been found close together, which suggests they may have lived in family groups.

How Big Were Baby Dinosaurs?

By the time you're fully grown, you'll have multiplied your birthweight by 20 times. Newly hatched duckbills were so tiny compated with their parents that they had to put on a 16,000-fold growth spurt to reach the same weight as their parents.

Did Dinosaur Young Stay With Thier Parents?

Scientists have found an enormous herd of duck-billed Maiasaura that were killed by a heavy fall of volcanic ash. The herd was made up of four distinct sizes of dinosaurs. Some think the two smallest were babies and youngsters. The two largest were probably teens and adults.

How Was Dinosaur Life As A Baby?

Baby dinosaurs probably grew up fast. Sauropods, which moved in herds, probably kept their youngsters in the middle as they traveled, protected by the adults on the outside.

As the Protoceratops juveniles grew, the shape of their sklls changed too. Juveniles had a much lower nose ridge. Adults developed a higher nose ridge which it used to butt opponents. Adults displayed a very large bony frill at the back of the neck. This was an area for the attachment of powerful jaw muscles. It was also a display structure: the larger the frill, the larger and more powerful the adult.

Little Triceratops hatched from their eggs looking quite round and cuddly. Fossils show that these dinosaurs didn't grow their impressive horns until they were yound adults - between two and four years old.

How Old Were Dinosaurs?

Growth rates depends on whether dinosaurs were warm or cold-blooded. Endothermic animals grow more rapidly than ectotherms.

If the Apatosaurus were endothermic, it took them 50 years to reach the adult weight of 30 tons.

If the Apatosaurus were ectothermic, it may have taken them 200 years or longer to grow that large.