Life Cycles of Animals

The life cycle of an organism refers to the sequence of developmental stages that it passes through on its way to adulthood. Mammals, reptiles, amphibians, birds, fish, insects and other invertebrates--they each have their own unique way of reproducing life. There is an amazing variety of life cycles within the animal world. Surprisingly, only about 3% of all animal species give birth to live young as part of their life cycle. Most animals lay eggs.

Animals need to eat, to grow, to be safe, and to reproduce. This is all part of the life cycle. Their bodies are adapted in a wonderful range of ways to solve these problems of survival.

Sample some of the following activities to learn more about the life cycle of animals.


Places To Go

The following are places to go (some real and some virtual) to find out about animal life cycles.

American Alligator
Virtually visit an alligator nest to learn more about the life cycle of these reptiles.
American Bald Eagle
Learn about the life cycle of some of the most magnificent birds in the world.
Ant Colony Cycle
Spend some time in an ant colony to learn about their life cycle.
Corals and Coral Reefs
Travel to a coral reef.The life cycle of coral is being disrupted by petroleum products and other chemicals dumped near coastal waters.
Life Cycle of a Frog
Visit a pond and spend some time with tadpoles and learn about the life cycle of frogs.
San Diego Zoo
Pandas rarely breed successfully in captivity. Take a cyber trip to the San Diego Zoo to learn about the life cycle of giant pandas.
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People To See

The City Naturalist - Earthworms
Chat with an earthworm. They are essential to the health of plants because they aerate the soil, add nutrients to the soil from their castings, and help recycle organic matter. They also have an interesting and unusual life cycle.
Dallas Jackman -
Mr. Jackman, a retired Granite school teacher, co-authored a textbook along with Linda Pearson about the animals of Utah. The textbook is called Outdoor Biology. Students are welcome to email him their questions about Utah animals.
E.B. White
Visit with E.B.White or spend time with his Charlotte the spider. When Charlotte's baby spiders hatch from their egg sac and go wafting off in the wind, it's all part of the life cycle of a spider.
Komodo Dragon
Carefully visit with a Komodo dragon and find out about their life cycle.
Rachel Carson
Spend some time with Rachel Carson. Her book, Silent Spring, was instrumental in educating us about the dangers of pesticides and how they can affect the life cycles of many kinds of wildlife.
Scientific American
Ask the experts at Scientific American your questions about life science and life cycles.
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Things To Do

American Egg Board
The people who bring us the Incredible Edible Egg advertisements have an interesting site with everything you ever wanted to know about chicken eggs.
Amphibian Embryology Tutorial
Click through this online tutorial about the life cycle of amphibians.
Anglerfish have an unusual life cycle. The tiny males bite into the female's skin and fertilizes her eggs. Then his mouth stays attached to her side for the rest of their lives. His blood fuses with hers, and he is completely dependent on her for food and oxygen.
Children's Butterfly Site
Print these pages about the life cycle of monarch butterflies. Birdwing butterflies are the biggest butterflies in the world. They have a wingspan of about 11 inches.
Flamingoes live in huge colonies. Flamingos mate for life. Both the male and the female help build a nest of mud. The female lays only one egg.
Koala Life Cycle
Learn about the life cycle of marsupials. The word marsupial comes from the Latin word marsupium which means "pouch". What is a baby koala called?
Life Cycle of a Mosquito
Learn about the life cycle of mosquitoes and what conditions they need in order to breed successfully. Bats like mosquitoes. Some bats can eat up to 600 mosquitoes in one hour!
Molecular Virology
Viruses are kind of like parasites because they enter living plant, animal, or bacterial cells and make use of the host cell's chemical energy and its protein and nucleic acid to replicate themselves.
Spend some time with a butterfly egg, larva, pupa, and adult and learn about the life cycle of a butterfly.
Nine-banded Armadillos
Nine-banded armadillos have an unusual aspect to their life cycle. They always give birth to four identical young, and these four babies always develop from the same egg.
Ostriches make a communal nest and many females lay their eggs there. Both males and females take turns incubating the eggs. Ostrich eggs are the largest eggs produced by any animal living today.
Scorpions are not insects. They are arthropods in the class Arachnida and are related to spiders.
The Spider Life Cycle
Find out how male spiders get the attention of females. Baby spiders are called spiderlings.
It used to be thought that sponges were plants. It's now known that they are animals. The life cycle of some sponges includes a process called budding. This occurs when a piece of the adult sponge separates and becomes a new sponge.
Tasmanian Devil
Tasmanian devils are also marsupials. They live on the island of Tasmania. Their pouch faces backwards--the opening is towards their tail.
Virtual Frog Builder
Play this virtual frog builder game to learn about the life cycle of frogs.
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Teacher Resources