Paternal care, tools to save teeth, & whale sounds | Last Week in Science (19 May 2024)

Father's love and care

There are only a few animal species (5% mammalian species) in which both the parents care for their offspring. Mouse is an example where male mice are known to care for the young ones along with the mother in some species like oldfield mice but in other species like deer mice only the mother cares for the young ones. Scientists have found that a new type of cell population are present in the male oldfield mice that are responsible for this behaviour of caring for their offspring.

Male mice are known to kill the new born pups because one litter may have more than one father. These mice are known to be promiscuous, i.e., have more than one mate. And there also exist species of mice that are monogamous, that have only one mate and these are the ones who are known to care for their young ones.

To understand the difference in the behaviour of these different species of mice, scientists studied a gland known as adrenal gland. Adrenal gland is present above the kidneys and produces adrenaline hormone that is known for the fight or flight response of the body in stress. The size of adrenal gland was found to be larger in oldfield males as compared to males of deer mice. Further study of the adrenal gland found one hormone 20 α OHP, which forms from progesterone - the female sex hormone, to be produced in the adrenal glands of the old field mice. 20 α OHP is also known to be produced in the ovaries of many species of mice. The scientists also discovered a new type of cell population in the adrenal glands that produced this hormone. This hormone then reached the brain via the blood stream and thus affecting the behaviour of male mice.

It is interesting to see that oldfield and deer mice are closely related but because oldfield mice evolved to have larger adrenal glands with cells that do not exist in deer mice made them monogamous.

Tools for dental health

Many animals are known to use tools. Sea otter is one example that uses stones, shells, glass bottles and trash to crack their food like snails, crabs and clams which have a hard shell. 

Soft bodied organisms like sea urchin are the preferred food of otters. In those times when sea urchins are not available, otters switch to hard shelled snails, crabs, and clams.

A group of scientists have been tracking 196 sea otters on the coast of California for a decade. They found that female otters use tools more often than males. They think that because females are not able to bite the hard shells as compared to males so the use of tools helps. Females need more energy than males because of caring for their young ones seems to be another reason to feed on hard shelled organisms that provide more energy than sea urchins. It is also the female otters who pass on the skill of using tools to their offspring, Another interesting finding in this study was that the teeth of female otters were less damaged as compared to the males. It appears that biting into the hard shell causes tooth damage and therefore, otters devised the technique of using different objects as tools.


Sounds of whale 

Whales are social creatures which live in groups. They have a sophisticated communication system that uses rhythmic sounds. Our current understanding of whale communication is that they produce clicks in a rhythmic pattern to communicate. This rhythmic pattern is called coda. It is known that there are some coda which are unique to a group of whales. These are called as identity coda and whales use it to identify members of their group. And the knowledge of the identity coda is passed on from one generation to the next. Identity coda is only a small set of sounds that are produced by whales. The other sounds produced by them are called as non-identity coda.

Scientists wanted to see the difference in the sounds produced by different groups of sperm whales. They found the identity coda to be highly different in the whale groups that live nearby. While it was interesting to see that their non-identity coda were similar. It appears that whale groups learn from each other as being in proximity they need to communicate amongst themselves while maintaining their group identity.

Reference: How neighbouring whale families learn each other’s vocal style


  1. Highly engaging post.
    I was thinking about the elegance of 'Sea otter'


Post a Comment