Wildlife Archives

Jellyfish life cycle and reproduction :

Images : Noaa Ocean Explorer, Wikipedia, Monterey Aquarium

Jellyfish are marine invertebrates of the class Scyphozoa, and can be found in every oceans in the world. The body of an adult jellyfish consists of a bell shape producing jelly and enclosing its internal structure, from which tentacles are suspended. Each tentacle is covered with cells called cnidocytes, that can sting or kill other animals. Most jellyfish use these cells to secure prey or for defense. Others, such as Rhizostomae, do not have tentacles at all.

Jellyfish lack basic sensory organs and a brain, but their nervous systems and rhopalia allow them to perceive stimuli, such as light and odor, and respond fast. They feed on small fish and zooplankton that become caught in their tentacles. Most jellyfish are passive drifters and slow swimmers, as their shape is not hydrodynamic. Instead, they move so as to create a current forcing the prey within reach of their tentacles. They do this by rhythmically opening and closing their bell-like body. Their digestive system is incomplete: the same orifice is used to take in food and expel waste.

Source : Wikipedia

The Orca or Killer Whale (Orcinus orca) is not a whale, but the largest species of the oceanic dolphin family (Delphinidae). They are sometimes referred to as blackfish, a group including pilot whales, pygmy and false killer whales, and melon-headed whales. It is the second-most widely distributed mammal on Earth (after humans) and is found in all the world's oceans, from the frigid Arctic regions to warm, tropical seas. It is also a versatile predator, eating fish, sea turtles, seabirds, pinnipeds, elasmobranchs, sirenians and even other cetaceans. This puts the orca at the pinnacle of the marine food chain. Orcas have been known to attack baleen whales, in particular gray and Blue whales.

Source : Wikipedia