Yet when most people think of these cartilaginous fish, a single image comes to mind: That generalization does sharks a huge disservice, as they have far more variety than that. They range in size from the length of a human hand to more than 39 feet 12 meters long; half of all shark species are less than one meter or about 3 feet long.
Reproduction Our knowledge of the many different types of reproductive strategies of sharks is still limited.
This variety is precisely why it is difficult to make a certain generalization on their reproductive methods, although these are what make sharks so successful.
Sharks have optimally adapted their reproduction to the most different conditions. Most sharks bear live young viviparityothers lay eggs. Several shark species mate the entire year, others prefer certain seasons and regions.
The females of some shark species bear young each year, others stop reproducing at irregular intervals which can last several years.
Viviparous shark - the birth of a lemon shark pup. In many aspects it resembles the reproductive method of mammals. The eggs are fertilized in the upper part of the fallopian tube and are encased in only a very thin membrane.
The females then retain the developing eggs in the last extended section of the fallopian tube which is thus termed the womb or uterus. Protected by the mother's body, the pups develop and are born as self-sufficient sharks following a gestation period of 6 to 22 months.
The size of the pups at birth is usually between 45 and 60 cm. These eggs are round to oval and are encased in a hornlike egg capsule. The protective egg capsules are composed of two to three cases and often have interesting shapes, e. This prevents the eggs from being swept away.
Normally the eggs are quite large, measuring 10 to 25 cm in length. They also have a large yolk which nurtures the embryos sufficiently with nutrients.
By laying their young in well protected, stable egg capsules with sufficient nutrients, the female sharks shorten the time needed to care for their young.Lesson Summary There are about species of sharks, most of which are carnivores. Some sharks are friendlier, like the nurse shark, leopard shark, and whale shark, which is a filter feeder.
With over species of sharks, there are many different shark sizes and shapes. The largest shark (and also largest fish) is the gentle whale shark (Rhincodon typus), which can reach lengths of 39 feet (12 meters). The smallest is the dwarf lantern shark (Etmopterus perryi) clocking in at only 8 inches long.
This tiny shark is found in deep waters off the coasts of Columbia and Venezuela. Sharks come in many different types of body shapes. Generally, sharks have a streamlined, torpedo-shaped body that can easily glide through the water. Although, some bottom-dwelling sharks--angel sharks-- have flattened bodies that allow them to hide in the sand of the ocean bed.
Blacktip Sharks are different than Blacktip Reef Sharks (this confused me for quite some time)! They are usually about 5 feet long although the longest on record was about 9 feet long. during breeding season every February and March, around 10, congregate along the Florida coastline.
In this lesson we'll be exploring three different orders of sharks. For each one, we'll look at examples of specific sharks, where they live, what.
Shark Summary - A shark summary explaining the major behavioral and anatomical features of sharks. Check out our shark summary and facts.