Shortfin Mako Shark

Isurus oxyrinchus

Yesterday we talked about the Viviparous Lizard, a reptile that gives birth to live young. Today's animal, the Shortfin Mako Shark, also gives birth to live young and are Ovoviviparous. This means that their young are incubated inside their bodies, but inside an egg sac, not a placenta. Once the eggs hatch, the offspring practice Oophagy while still in the uterus. This means that they consume all of the unfertilized or underdeveloped eggs. Gestation can last as long as 18 months, and as many as 18 pups can be born at a time!

Shortfin Mako Sharks also have the interesting distinction of being very, very fast. Their bodies are remarkable hydrodynamic, and they have been clocked at speeds of 31mph (50kph). Their is even some evidence that they can swim in fast bursts of 46mph (74kph)! They can also leap several feet into the air!

One biological feature that allows them to move so fast is their circulatory system. It allows their body to be several degrees warmer than the water that they swim in, which lets them be more active. (Great Whites have a similar system)

Fishing for both food and sport has caused this species to be listed as Vulnerable. They also do very poorly in captivity, and the longest one held only lasted a few days.

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IUCN Status : Vulnerable
Location : Tropical Waters Worldwide
Size : Body Length up to 10ft (3.2m)

Classification : Phylum : Chordata -- Class : Chondrichthyes -- Order : Lamniformes
Family : Lamnidae -- Genus : Isurus -- Species : I. oxyrinchus