Animal adaptation is one of the topics for the Primary School Leaving Examination for Science. Since the exam is next Tuesday, I got a rush of adrenaline that motivated me to compile this from various textbooks and assessment books. Maybe you will find these adaptations intriguing
Adaptations for keeping cool
- A hippopotamus submerges itself in the river during the day and emerges from it at dusk to graze on the grasslands. During the day, the surrounding temperature is high, since the temperature of the water is lower than the surrounding temperature, the hippopotamus submerges in there. At dusk, the surrounding temperature is lower than that of the day, so it grazes on the grasslands.
- A warthog rolls about or lies in mud to cope with high temperatures. This is because mud is a poor conductor of heat and does not allow heat to pass through it quickly. The mud is hence not as hot as the surroundings.
- When animals sweat or pant, water that evaporate from the skin or from the mouth helps to cool their body. When perched on their nests, birds may pant heavily - breathing up to 300 times a minute - to lose heat!
- Cats keep themselves cool by licking themselves. The saliva evaporates, producing a cooling effect.
- Kangaroos lick their front legs so that heat is lost from their bodies when the saliva evaporates.
- Desert tortoises dribble urine over their back legs and saliva over their necks and front legs to cool down.
- Desert birds like owls and nighthawks lose excess heat by rapidly fluttering their throat to allow evaporation of water from their mouths.
- Fennec foxes have large ears that act as radiators which increase the exposed surface area. This allows them to lose heat to the surroundings and cool down more quickly. Warm blood pumped through their ears help them lose heat from their bodies to the surroundings.
- African elephants have larger ears than Asian elephants. That’s because African elephants live in warmer climates, and their larger ears help radiate excess heat, regulating body temperature.
- Animals lose body heat as their blood flows through blood vessels near the skin. This is because the surrounding air is cooler than their blood. The extra large ears of the African elephant and jackrabbit provide large surface areas for heat loss to the environment. The jackrabbit’s large ears have many blood vessels near the skin to increase heat loss.
- Animals usually stay in burrows or caves in the day to prevent overheating. They will be less exposed to the sun and gain heat slower. They are only active at night when it is cooler.
- Desert plants have needle-like leaves to minimise the loss of water through transpiration
- Evergreens, such as conifers, retain their leaves during winter because they have needle-shaped leaves with thick, wavy coatings to minimise water loss and grazing
- Some, like the saguaro cactus, can store large amounts of water in their stems
- Some desert plants have an extensive, widespread network of shallow roots to absorb rainwater quickly when it rains. Other desert plants have deep underground roots to reach water stored far beneath the surface.
- The acacia tree sheds its leaves to minimise the loss of water through transpiration and slows down growth, thus helping it use less water, food and energy.
- Deciduous trees such as maple and oak shed their leaves during winter. This helps them reduce water loss through transpiration, and minimise damage by herbivores. They survive the winter on food stored in their roots.
- The living stone plant exposes only a few of its leaves to the Sun. The rest of the plant remains underground, away from the direct heat of the Sun.
- Some annual plants, like tomato and pea plants, die within a year, before winter arrives. Only their seeds are left to survive the winter. The seeds will germinate when warmer spring temperatures return the following year.
Adaptations for keeping warm
- Animals living in cold habitats (like whales and seals) have thick fur or blubber (oily fatty tissue) to help keep warm. The layer of fur/fat is a poor conductor of heat and slows down heat transfer from the body to the surroundings. Fat is also a good store of energy.
- Many mammals have 2 layers of hair. The inner layer consists of soft hair, which traps air and acts as a blanket, while the outer layer has longer, coarser hair that protect against the weather and injury.
- Some animals have oil on their fur or feathers to repel water so that less water will freeze on their bodies, hence reducing heat loss
- Fur and feathers are less effective in trapping heat once they get wet. This is why seals have a thick layer of blubber in addition to their double layer of fur.
- Reptiles keep themselves warm during winter by finding shelter in holes or burrows
- Grizzly bears hibernate during cold weather. Their life processes like respiration and digestion slow down and stay that way for a few months. They become active again when the weather is warmer.
- During the dry season in East Africa, wildebeest abandon the grasslands and travel about 300 kilometers in search of food and water!
- The Cape ground squirrel of the Kalahari Desert uses its bushy tail as an umbrella, increasing the amount of time it can spend outside its burrow looking for food.
- Low-bush cranberry trees have thick, wavy leaves. They help prevent injury to the leaves from frost and also help protect the leaves from being dried out by harsh winter winds