By Blaise Jones
Sharks have been on this planet longer than the dinosaurs were. They’re perfectly adapted to their environments, utilizing an amazing array of physiological and sensory adaptations to dominate their ecosystems. They are speed, strength, and agility all wrapped up in a muscular body coated in an armor of teeth strong as steel. They are not, however, good parents.
The extent of a mother shark’s care for her offspring goes as far as giving birth. Mother sharks carefully pick the areas in which they give birth, typically favoring areas of shallow water with a lot of structure to help provide protection, prey, shelter and camouflage for newborns. Estuaries and mangrove forests are especially popular birthing places for sharks. After the mother shark finds just such a place and gives birth to her pups she leaves, never to see her pups again.
These shallow areas are brimming with small fish for the newborn shark pups to hunt and eat. Shark pups are born fully formed and are able to swim and hunt as soon as they leave their eggs or mother’s body. The shallow waters of estuaries and mangroves prevent bigger adult sharks, which prey upon shark pups, from attacking.
While a mother shark does not actively protect her offspring, she purposefully gives birth to them in an area that provides their best chance for survival. Pregnant sharks also spend a great deal of energy making sure they have the healthiest offspring possible.
K selected sharks
Sharks give birth infrequently and to very small numbers of offspring; and female sharks tend to be larger than the males. Both of these traits are found in “K-Selected” animals.
K-selection refers to animals that do not have many offspring at one time, but instead have only a few and focus their care on their one or two offspring. K-selection animals often give birth to larger offspring that are highly developed and usually require additional care from the parents after birth. Advanced mammals such as whales and humans are K-selective animals.
Sharks, however, are an odd case of K-selection. Sharks do not care for their offspring after birth because newborn pups do not need the additional care. Aside from their vulnerable size to predation, shark pups are fully capable of surviving on their own without any extra care from their parents.
The reason sharks take so long to give birth and they breed so infrequently is because the mother shark needs to gather up enough extra energy to provide for her litter of pubs as they grow to full form and functionality inside of her. Instead of spending the extra time caring for semi-developed offspring, sharks are able to give birth to fully independent pups ready to face the world.
“Sharks: The Animal Answer Guide” by George H Burgess and Gene Helfman
“The Encyclopedia of Sharks” by Steve Parker