Biology Science Fair Project Ideas
Do you have an interest in biology? These are great biology-based science fair projects! Does alcohol or tobacco affect seed germation? Is the water in an day-old water bottle safe? How many teeth does sand dollars have? These are all questions that make for great biology science fair projects! Each science fair project includes 15 pages of easy-to-follow directions to help you create your project step-by-step.
Also included in each project:
- Details about the scientific method
- List of needed materials
- Vital information on how to make your presentation
- Details about "What the judges are looking for"
As a bonus, every project includes 16 free original science games that you can play with all your friends!
In addition to these biology science fair ideas, you can choose from over 200 winning science fair project ideas . Every subject is covered including chemistry, physics, biology, computer and environmental sciences, and more. Choose it and print it now; start your science fair project right away!
Just for Fun Biology Facts!
Animals offer interesting biology science fair
project ideas. If you are looking for biology science fair project ideas
consider doing a study of an animal. Science fair project ideas involving
animals include studying the behavior of animals. If you need biology
science fair projects, observing feeding habits offer more free science fair
Marsupials — Life in a Pouch
Marsupials also have tiny, undeveloped young, but they grow inside the
mother’s body instead of in an egg. When they are born, they climb up the
mother’s fur to a pouch on her belly and settle inside. They latch onto a
nipple and nurse almost continually until they have grown enough to emerge
from the pouch. Some well-known marsupials are koalas and kangaroos.
Placental Mammals — Just Like Us!
Placental mammals are the largest group, and their young develop inside
the mother’s body while attached to a placenta. This is an organ that
gives them nutrients and oxygen from the mother’s blood, and it allows
them to grow and develop to a more advanced stage before being born. Some
examples of placental mammals are cats, bears, monkeys, and humans.
The Large and the Small
There are more than 4,000 species of mammals, which taxonomists classify
into different groups based on characteristics like their body structure,
the number and type of bones, and the number and arrangement of teeth. The
smallest mammal is the Kitti’s hog-nosed bat Craseonycteridae thonglongyai,
which only weighs 0.05 ounces (1.4 grams), and the largest is the blue
whale Balaenoptera musculus, which can be 100 feet long (30.5 meters) and
weigh 150 tons (136 metric tonnes). The largest land mammal is the male
African elephant, which can reach 10.5 feet (3.2 meters) at the shoulder
and weigh up to 15,000 pounds (6,810 kilograms).
What’s In a Name?
“Hippopotamus” comes from a Greek word meaning “water or river horse.” But
hippos are not related to horses at all—in fact, their closest living
relative is the pig!
The Large and the Small of It
Common hippos Hippopotamus amphibius are the third heaviest land mammals
on Earth (after the elephant and rhinoceros), and much bigger than the
pygmy hippos Hexaprotodon liberiensis. There are several other differences
between common and pygmy hippos, such as the pygmy hippo’s relatively
longer limbs and the fact that it is less adapted for living in water than
its huge cousin. Common hippos have webbing between their toes, which aids
in their dog paddle swimming style. Pygmy hippos are also much rarer,
found only in the interior forests of small parts of Africa, and little is
known of their habits.
Come On In, the Water’s Fine!
With its eyes, ears, and nostrils on the top of the head and nose, the
hippo can hear, see, and breathe while most of its body is underwater.
Surprisingly, however, hippos cannot swim! Their bodies are far too dense
to even float, so they move around by pushing off from the riverbed or
simply walking along the bottom in a slow-motion gallop, lightly touching
the bottom with their toes like aquatic ballet dancers.
Nighttime Is the Right Time
During daylight hours, the common hippo spends almost all its time
wallowing in shallow water. In the evenings, after the hot sun has set,
common hippos come out of the water for a night of grazing—in fact, this
goes on for about six hours! A single hippo can eat up to 100 pounds (45
kilograms) of grass in a single night, returning to the water before
sunrise. While hippos like to feed on patches of short grasses (called
“hippo lawns”) close to water, sometimes they must travel several miles
(kilometers) to find food, making long trips on land to new lakes or
rivers. At the San Diego Zoo, the hippos are fed herbivore pellets,
alfalfa and Bermuda hay, lettuce, and on special occasions, melons.
Baby, You’re the Greatest!
Pregnant females actually separate themselves from the herd as the time of
birth nears. Typically, common hippo calves are born underwater. They must
quickly swim to the top to catch their first breath, close their nostrils
as their parents do, and then submerge to nurse. Yet it is not quite as
difficult as it might seem: hippo calves are able to do all this only
minutes after birth.
What’s that I “Herd”?
Common river hippos live in herds of about 10 to 30 animals, but they have
been observed in groups as large as 100. The dominant male has the right
to mate with all females in his herd, although he will sometimes allow
subordinate males in and around his territory to mate. His territory is
also well marked with dung, and this effective scent mark warns other
mature males to stay out. If a fight between rival males develops, hippos
are capable of injuring each other with their long canine tusks, and they
have been known to die as a result of a very aggressive battle.
Pygmy hippos tend to be solitary. However, sometimes the home ranges of
several animals will overlap.
What's in a Name?
Rhinoceroses get their name from their most famous feature: their horns.
The word rhinoceros comes from the Greek rhino (nose) and ceros (horn).
For ages, rhino horn has been used to treat illnesses, especially fevers.
Yet like our fingernails and hair, rhino horn is made of keratin and has
no healing properties. In some countries, rhinos are being dehorned, a
process that removes the valuable horn but leaves the animal alive and
well. This prevents poachers from killing rhinos for the money their horns
The five types of rhinos are the Sumatran, Javan, black, white, and Indian
rhinos. Javan and Indian rhinos have only one horn, while Sumatran, black,
and white rhinos have two. What they all have in common are large heads,
broad chests, thick legs, poor eyesight, excellent hearing, and a fondness
for rolling in the mud. Because they are very nearsighted, they often
charge when they are startled. This has given them an undeserved
reputation for having a bad temper. All rhinos are herbivores, eating
grasses or leaves, depending on the species. At the San Diego Zoo's Wild
Animal Park, the rhinos are fed hay and high-fiber biscuits, along with
carrots and apples.
African Rhinos: Black and White
Black rhinos Diceros bicornis and white rhinos Ceratotherium simum are the
same color—they're both brownish gray! How the white rhino came to be
called “white” is uncertain. One account says that South Africa's early
Boer settlers called it wijde, Dutch for “wide,” which could refer to the
wide lip or the size of the animal. The wide mouth of the white rhino is
perfect for grazing on grasses, while the more narrow, prehensile lip of
the black rhino is great for pulling leaves and shrubs into its mouth.
Other names used for these two rhinos are “broad-lipped” and
"hook-lipped." Guess which name belongs to which rhino!
Meet the Asian Rhinos
Indian rhinoceros Rhinoceros unicornis— The mouth of the Indian rhino
looks like a cross between broad-lipped and hook-lipped. Although it is
fairly broad, it has a small prehensile lip. Many people describe these
rhinos as armor-plated, but they are actually covered with a layer of skin
that has many folds. Also called the greater one-horned rhino, they are
native to swampy areas of Northeast India and Nepal.
Javan rhinoceros Rhinoceros sondaicus— Like the Indian rhino, the Javan
has a single horn. It is also called the lesser one-horned rhino. Javan
rhinos are very rare in the heavily forested areas of Southeast Asia, and
they are probably the rarest of the rhino species. Scientists have devised
an interesting way of counting them. Throughout the rain forest, they have
set up cameras with sensors. When the rhinos pass the sensor, the camera
takes their picture! The scientists can then count them. Learning more
about these jungle rhinos in the wild will help protect them from becoming
Sumatran rhinoceros Dicerorhinus sumatrensis— This is the smallest and
hairiest of the rhinos. It is also one of the most endangered. Very little
of its native habitat is left on the island of Sumatra. There has been
little success in breeding this species in zoos.
The Wild Animal Park has the most successful captive breeding program for
rhinos anywhere in the world. When the worldwide population of southern
white rhinos numbered less than 2,000, a male at the Park sired 50 babies!
Many black and Indian rhinos have been born here, too.
The first black rhino born at the San Diego Zoo was named Werikhe in honor
of Michael Werikhe, “the rhino man.” Mr. Werikhe was a Kenyan
conservationist known for his long "rhino walks” to educate people about
the plight of the rhino and to raise money to support rhino reserves. He
is a good example of what one person can do to make a difference! And
because all rhino species are now endangered, they need our help to
Baby, It’s Cold Outside!
Polar bears live on ice and snow, but that’s not a problem—these bears
have some cool ways to stay warm!
Hair— A dense, thick undercoat of fur is protected by an outer coat of
long guard hairs that stick together when wet, forming a waterproof
barrier to keep them dry. Even though polar bears look white, their hair
is really made of clear, hollow tubes filled with air. This hollow hair
helps direct the sunlight to the bear’s black skin, acting like a solar
Blubber— Blubber helps insulate polar bears from the freezing air and cold
water, and acts as a nutritional reserve when food can’t be found. This
blubber also helps the bears float in the water. It is 2 to 4 inches (5 to
10 centimeters) thick.
Winter Sleep— When the temperature outside drops, many bears stay warm by
making a den and sleeping. Polar bears do not hibernate, but their body
functions do slow down at this time. Many scientists call this “winter
sleep,” because the bears can easily be awakened. A mother polar bear can
give birth and nurse her young while still in her winter sleep.
What’s on the Menu?
Polar bears are mainly meat eaters, and their favorite food is seal. They
will also eat walrus, fish, caribou, beached whales, grass, and seaweed.
Polar bears are patient hunters, staying motionless for hours above a
seal's breathing hole in the ice, just waiting for a seal to pop up.
Unfortunately, many bears have learned to eat at garbage dumps. They could
be injured or poisoned by trash, and it puts the bears in close contact
with humans. This can be a dangerous situation for both humans and bears!
Polar bears at the San Diego Zoo get a ground-meat diet made for
carnivores, dog kibble, trout and other fish, as well as root vegetables
and lettuce. Cow femur bones and thawed rabbits are added once or twice
Noses with Legs
The polar bear's nose is so powerful it can smell a seal on the ice 20
miles (32 kilometers) away, sniff out a seal's den that has been covered
with snow, and even find a seal's air hole in the ice up to one mile (1.6
kilometers) away. No wonder many people call them "noses with legs!"
Den Mothers and Cubs
For such a big animal they sure start out small! A cub is about the size
of a rat when it is born. The mother bear digs a cozy den in the snow to
have her cubs. The den is no bigger than a telephone booth, but it can be
about 40 degrees warmer in there. Usually two cubs are born to each mother
between December and January. They are hairless and blind at birth, and
depend on their mother to keep them warm and fed.
Milk from polar bear mothers is 35 percent fat, the richest milk of any
bear species. This helps the cubs grow quickly, and by April they weigh
more than 20 pounds (9 kilograms) and start exploring with their mother
outside the den. At about two years of age they are ready to be on their
Who's the Biggest?
Both polar bears and brown bears are big, and are the largest land
carnivores. But most experts agree that polar bears are the tallest bears,
getting up to 10 feet (3 meters) long.
What About the Future?
For a while, polar bears were in trouble. People killed them just for
trophies, and they were losing some of their wild places to live as people
started moving into their territory. Global warming has affected polar
bears as well, as ice sheets are melting, preventing the bears from
traveling in search of food. Many countries got together to help this
magnificent bear by preserving its habitat and setting up hunting
restrictions. Polar bears are doing better now, but still need our help.
People must continue to give these bears large, safe places to live, and
try to keep the environment clean and free of pesticides that could poison
the bear's food.