Living in Social Groups

What are Social Groups?

Some animal species live together in social groups. These social animals regularly interact with others of the same species, and an individuals success depends on how well the group is working as a whole. Two kinds of social groups are Eusociality and Prosociality.

Eusociality

Eusociality is the most advanced organized social group in nature. The characteristics that define one of these groups is taking care of offspring from other individuals, multi-generational family groups, and different labor groups of reproductive and non-reproductive. In these groups it is often only a single individual or a very small group that actually reproduce. This allows for a majority of the colony to take part in extreme task specialization. These tasks can be gathering food and resources, building the shelter or protecting the rest of the colony.  These “workers” are thought to forgo reproducing because of constraints on independent breeding. These include food shortages, territories, protection, nest sites, and available mates. Although workers may never reproduce, there are fitness benefits  that are gained by aiding the reproduction of a queen. Some examples of animals that live in eusocial groups are ants, bees, wasps, termites, and the naked-mole rat.

Image result for ant colony

“Safari Ants”
By Mehmet Karatay under  Creative Commons Attribution-Share Alike 3.0 Unported

Prosociality

Prosocial behavior benefits many individuals or a society as a whole. It is similar to eusocial behavior but not as complex. They will often live together, have cooperative care of young, and divide up reproductive labor and other tasks. This is done by helping, sharing, informing, and volunteering. Informing is important because it involves providing information that other individuals need, such as warning someone of danger. Sharing involves a resource being given up by one member of the group to benefit another member, such as offering a piece of food to an individual that has none. Some examples of animals that exhibit prosocial behaviors are locusts, chimpanzees, and many types of birds.

Examples of Social Groups

Rhesus macaques (Old world monkeys)

Rhesus macaques usually consists of about 20-200 males and females, however the females typically outnumber the males, sometimes by a ratio of up to 4:1. The males and females both have separate hierarchies. The females use matrilineal hierarchies which means her rank depends on the rank of her mother. A single group may have multiple matrilineal lines, and a female will outrank any unrelated females that rank lower than her mother. Mothers seem to prevent the older daughters from forming coalitions against them. Each daughter has a high rank in her early years, so rebelling against her mother is discouraged. The males also have matrilineal lines until they reach the age of four to five years old. Then they are driven out of their groups by the dominant male. The only way for a male to gain dominance is by age and experience.

File:Rhesus macaque Macaca mulatta (2154440309).jpg

“Rhesus macaque” by Paul Asman and Jill Lenoble Under  Creative Commons Attribution 2.0 Generic

Penguins

Penguins all breed in large colonies, except for the yellow-eyed and Fiordland species. The size of these colonies can range from as few as a 100 pairs, which is the case for gentoo penguins, to several hundred thousand with king, macaroni and chinstrap penguins. Because the colonies are so large, there is a  high level of social interaction between the birds. This leads to a large variety of visual and vocal displays in the penguin species. Agonistic displays are intended to confront or drive off other individuals.

Penguins form monogamous pairs for a breeding season. Most penguins will lay two eggs in a clutch, although some of the larger species only lay one. All penguins share the incubation duties except for emperor penguins. Emperor penguin males do all of the incubation work. These incubation shifts can last days or weeks as one member of the pair feeds at sea.

When mothers lose a chick, some will attempt to steal another mother’s chick, though they are usually unsuccessful. This is because other females that are around will assist the defending mother.

Image result for penguin colony

King Penguin colony” by Scott Henderson Under Flickr

Bees

Bees are an example of a eusocial group. A colony of honey bees can contain up to 30,000 bees, each one having a specific function or task.  Some bees are meant to breed, some to collect nectar, others maintain the hive and some process the collected nectar in the hive. The bees possess communication tools that help the productivity of their hive-mates.

The queen’s purpose is to populate the colony. She is the only female in the colony that is able to reproduce. She is larger than the other bees and can live up to about 5 years, although her productivity usually ends after she is 3 years old. When the queen dies, becomes lost, or is removed, a new queen must be selected from worker bee larvae. The queen candidate will be hung vertically on the surface of the comb and will be provided large quantities of food.

Drones are present during mating season. They are the largest bees in the colony and do not possess stingers, pollen baskets, or wax glands. Their job is to fertilize the queens’ eggs.

Most of the colony is made up of workers. These bees have brood food glands, scent glands and pollen baskets, which allow them to work inside and outside the hive. They are responsible for cleaning the hive, feeding the brood, caring for the queen and guarding the hive. They search for nectar, pollen and plant sap, and bring them back to the colony.

Inside The Bee Hive Free Stock Photo - Public Domain Pictures

“Bee Hive” Under CC0 Public Domain

Lions

Lions living together are called prides. There are usually five or six females, their cubs, and up to two males. Although there are sometimes two males, only one will be the dominant male and allowed to mate with the females. All of the adults in the pride will work together to protect each other from predators,  however there is a hierarchy that determines who will be dominant in that fight to protect them. Some of the lions duties are to cover the outer perimeter while the others remain well protected inside of it. There can be large battles between prides of lions over territory. The social structure of the lions also effects their eating patterns. When they make a kill, females involved with it will eat first. What is left has to go through the hierarchy of the pride.

File:African lion, Panthera leo, a pride at Pilanesberg National ...
“African lion pride at Pilanesberg National Park, South Africa” By Derek Keats, Under Creative Commons Attribution 2.0 Generic

4 thoughts on “Living in Social Groups

  1. Nice summary of group living for these species! Can you think of some similarities and differences in terms of the possible indirect fitness and/or direct fitness benefits to these behaviors for some of the animals that you talk about here?

    Liked by 1 person

    1. In bee colonies, the genetic diversity is a large fitness benefit. With penguins, being in these large colonies is an example of safety in numbers. With a ton of other penguins around them, predators are less likely to get them and their offspring than if they were off by themselves.

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  2. I really liked reading this post and it is similar to one that I wrote! I find it so interesting in social groups there are specific tasks that each individual has whether it be mating, collecting food, or working. I wonder how they decide which individual does each task? That would definitely be something cool to research. Great job!

    Like

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