What Are The Differences Between Mammals And Insects?


It is not hard to differentiate between an insect and a mammal. I wanted to find out the main differences between them.

Insects are invertebrates and have an exoskeleton whereas mammals are vertebrates with a backbone. Mammals give birth to live young whereas the life cycle of an insect is very different. Insects are great pollinators and are light enough to fly.

If you want to find out the differences between mammals and insects then please read on.

When you watch insects flying around on a summer’s day, or a beautiful butterfly on a flower, it is hard to see any similarities with mammals.

We know that they are looking back at us and must have similar bodily functions – to a degree. We also know they are driven by a similar, primal desire to find food and reproduce.

Are there any similarities between insects and mammals? Or, are the differences so extreme that they don’t share any traits at all?

Exoskeleton

The most crucial difference between mammals and insects is their skeletal system.

The most important distinction is that mammals are vertebrates while insects are invertebrates. What this means is that mammals have a familiar skeletal structure and central nervous system. The name comes from the presence of a backbone with vertebrae in the spinal column. 

Insects don’t have a backbone. Instead, many have different body parts such as the thorax and the abdomen. These features are clear on creatures like ants and some beetles.

Many insects will also develop a tougher exoskeleton as a form of protection. But, this isn’t the case with all insects. Bees, for example, have soft bodies. Arthropods will have this exoskeleton, much like arachnids and crustaceans. 

The exoskeletonprevents damage to their soft organs and stops them from drying out. Some will shed this when entering a new phase of development.

We can’t look at the difference between these exoskeletons and soft-bodied mammals without looking at a couple of mammalian oddities. 

The armadillo and pangolin both use protective plating to shield themselves from harm. They can roll up, tucking in the soft, vulnerable parts of their bodies to avoid harm. To a lesser extent, we see a similar defense mechanism with hedgehogs.

Life Cycle

Another important distinction is the life cycle of the insect versus that of mammals.

The reproductive traits of the vast majority of mammals rely on fertilization, gestation, and then the birth of live young. It is the same for rodents and canine species as it is for primates and ourselves. 

A mammals embryo develops in the womb with nutrients from the mother until they are ready to be born. It doesn’t matter if its one elephant, twin calves, a litter of eight pups, or the ongoing cycle of rabbits and rats.

Insects do things differently. Typically, adults will lay eggs, which develop into a larval stage of development. These larvae will grow bigger and stronger, feeding on plants or other insects. Eventually, they will metamorphasize into their adult form. 

The differences between adolescent and adult stages can be remarkable. One of the most well-known is the process from caterpillar to butterfly via delicate cocoons. Dragonfly larvae can spend years at the bottom of a pond before crawling out on the reeds and emerging as winged adults. 

Mayflies only get to be adults for one day where they end in columns of frantic activity trying to mate before they die.

Another difference here is that you don’t get the same parental care with insects as you do with mammals. 

There are some species of wasp and bee that are fantastic parents when it comes to making a safe nest for their young. Mason wasps will build little chambers to lay each egg within to keep it safe. Some parasitic wasps will create nests with paralyzed prey so that the young have something to eat when they emerge. But, once they leave the nest, they are on their own. 

This reason is why so many insects have so many young at once. Masses of new insects emerging at once means that there are too many for birds and bats to eat. This is known as predator satiation. This gives them an increased chance to survive. Fish do something similar when they lay masses of eggs.

Number Of Offspring

Mammals don’t have anywhere near the same amount of young as insects.

Large mammals and predator species will have a few cubs or pups and put their energy into raising as many as possible. Mammals generally don’t have the resources, energy or access to milk for too many hungry mouths. 

Primates and larger mammals tend to put their efforts into raising one baby at a time, often with the help of the rest of the family group. This is partly because the young take a while to mature and learn all the skills they need. Orangutans, for example, will stay with the mothers for around 6 to 8 years.

But, there are prey species that reproduce in quick succession with large numbers of babies. This is due to the idea of predator satiation similar to that of insects and fish. Knowing that infant mortality rates are high they increase the chances of some successful offspring. One of the larger litter numbers in mammals is the tenrec that can have up to 32 at a time.

Colonies, Family Groups, And Packs

This idea of the numbers of insects and mammals leads to the differences in colonies, family groups, and packs. 

Mammals typically live in small family groups or as solitary individuals. For the former, this could be a pack of wolves or prairie dogs that live and hunt together. It could be an extended family group of meerkats with their own hierarchy. 

Prey animals like deer will stick together in herds where there is safety in numbers. Rabbits and meerkats will have strong colonies with their own roles and secure underground homes. 

Solitary animals, like mountain lions, will hunt and find shelter on their own within their own territories. They will find females when the time comes to mate but that is normally the only time.

There are many species of insects that rely on the order and security of the colony. One of the best examples is the society of the ants, where large colonies work together to find food and create the best possible home. 

Termite mounds take this to a more obvious extreme. Beehives are quite similar, with worker bees collecting pollen and bringing it back to the hive to make honey.

Pollinators

This factor with the bees leads to another important point about insects. We rely on insects of all kinds, not just bees, to act as pollinators. They transfer the pollen from flower to flower to fertilize them and help with their own reproductive cycle. 

Pollination is something that we tend to associate with insects alone. It is one of the driving forces behind campaigns to plant wildflowers that bees and other insects actually like to visit. However, mammals do play their part in the life cycle of plants and trees too.

The insects may have pollinated the flower to produces seeds and fruit. But, something needs to disperse all those seeds out into the wider environment so there isn’t too much competition for light and nutrient. This is where many mammals come in. 

All kinds of species will enjoy the taste of fruit and nuts and get energy from them. Monkeys will take fruits high in the canopy. Squirrels will take nuts and bury them in caches elsewhere. Those forgotten or left behind can germinate into new trees. 

All sorts of opportunists will take a tasty treat from a hedgerow. When the seeds pass through their digestive system they are deposited in a new location.

Flight

There are lots of insects that take to the skies. Bees, butterflies, and dragonflies are among the most well-known. There are also countless species of fly in the world. Then there are all the bugs that have wings tucked under wing cases. This can come as a surprise to some kids as they watch ladybugs.

The ability to fly is a crucial distinction between the larval stage of insects and their adult forms. Flying makes a lot of sense when you are the size of an insect. It helps them travel between home and their source of food. It also means that they can migrate with ease, as is the case with a lot of butterfly species.

For mammals, flying isn’t a necessity. There is no need to fly between locations because there is no advantage to being up in the air. All the food as at ground level – unless you hunt birds and can leap in the air like a caracal. 

Their home range isn’t always big enough to need wings to travel long distances. Many are also so heavy that they wouldn’t get off the ground.

However, some squirrel species have developed flaps so that they can glide and bats do have wings which they use to hunt moths and insects at night.

There are slight similarities, but not many.

Insects play an important role in their habitat and our forests, grasslands, and garden depend on them in similar ways to mammals. We can also see similar traits as they use predator satiation and complex colonies to survive and reproduce. But, so much about the physiology and behavior of these invertebrates are vastly different.

Sources:

http://www.uky.edu/Ag/PAT/cat1/complife.htm

https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/insect-colonies

https://www.si.edu/spotlight/buginfo/insect-flight

Bryan Harding

Bryan has spent his whole life around animals. While loving all animals, Bryan is especially fond of mammals and has studied and worked with them around the world. Not only does Bryan share his knowledge and experience with our readers, but he also serves as owner, editor, and publisher of North American Mammals.

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