Which animals have more than one heart?

Which animals have more than one heart?

Humans have one heart. Most animals have one heart, but there are animals with no heart, such as the jellyfish, and there are animals with more than one heart.  

The heart transports, or circulates, oxygen in the blood around the body. This is called the circulatory system. The human heart has red blood cells called haemoglobin. The human heart has 4 chambers (two atria and two ventricles). The cockroach, for example, has one heart with 13 chambers. The earthworm has 5 pseudo-hearts (false hearts) that are really aortic arches that act similar to a heart. 

Continue reading “Which animals have more than one heart?”

Milky Jellyfish

The Milky Jellyfish (Chrysaora lactea) is a soft-bodied, invertebrate sea nettle in the Pelagiidae family of marine (saltwater) jellyfish. An invertebrate is an animal with no bones.

The Milky Jellyfish has a translucent (see-through) bell-shaped or umbrella-shaped dome body. It has short tentacles (limbs) with short arms. It has no bones, no brain, no heart, no blood, no excretory system, and no gills or lungs. It has nerve receptors in its body that enables it to detect smell, light, pressure, and touch. It is about 98% water.

Continue reading “Milky Jellyfish”

Box Jellyfish

The Box Jellyfish (Chirodropus sp.) is a marine (saltwater) planktonic scyphozoan in the Chirodropidae family of venomous box jellyfish. It belongs to the Cubozoa class. It is a cnidarian. It is also known as the Sea Wasp.

The medusa form of the Box Jellyfish has a cube-shaped, or box-shaped, bell. From each of the four lower corners hangs short stalks called pedalium which have about 15 slender, hollow tentacles. The rim of the bell is folded inwards to form a shelf known as a velarium. The velarium creates jet propulsion, which makes it move through the water. 

In the centre of the box is a manubrium, which looks like an elephant’s trunk. This is where its mouth is located. Other jellyfish have ocelli, which are light sensing organs, instead of eyes. However, the Box Jellyfish has about 20 ocelli in addition to true eyes, set in a cluster, with retinas, corneas, and lenses. The eyes are located in pockets halfway up the outer, flat surface of the bell.

Continue reading “Box Jellyfish”

Upside-Down Jellyfish

The Upside-Down Jellyfish (Cassiopea ornata) is a marine (saltwater) planktonic scyphozoan in the Cassiopeidae family of upside-down jellyfish. It is a cnidarian. It is also known as the Sunbathing Jellyfish. 

It is a photosynthetic jellyfish. It is the only jellyfish that rests with its bell or umbrella on the ocean floor and its tentacles pointing upwards. It does this to receive light so that the symbiotic algae living on it can produce carbohydrates for the jellyfish to use as food for energy. 

Continue reading “Upside-Down Jellyfish”

White-Spotted Jellyfish

The White-Spotted Jellyfish (Phyllorhiza punctata) is a marine (saltwater) planktonic scyphozoan in the Mastigiidae family of jellyfish. It is a cnidarian. It is also known as the Floating Bell, the Australian Spotted Jellyfish, or the Brown Jellyfish.

The White-Spotted Jellyfish has a deep-brown colour due to the algae living on the tissue. It has a bell-shaped dome with little spots. It does not have stinging tentacles. It does not have eyes. Instead, it has light-sensing organs called ocelli. It is composed of 95% of water, which enables it to float.

Continue reading “White-Spotted Jellyfish”

Spotted Jellyfish

The Spotted Jellyfish (Mastigias papua) is a small marine (saltwater) planktonic scyphozoanin the Mastigidae family and the phylum Cnidaria of jellyfish. It is also known as the Lagoon Jellyfish, the Golden Medusa, or the Papuan Jellyfish.

The Spotted Jellyfish has a bell-shaped dome with little spots. It does not have stinging tentacles. It does not have eyes. Instead, it has light sensing organs called ocelli. It is composed of 95% of water, which enables it to float.

Continue reading “Spotted Jellyfish”

Pacific Sea Nettle

The Pacific Sea Nettle (Chrysaora fuscescens) is a marine (saltwater) planktonic scyphozoan in the phylum Cnidaria of jellyfish. It is also called the West Coast Sea Nettle.

The Pacific Sea Nettle has a golden-brown bell-shaped dome with a reddish tint. From the bell, there are 24 long reddish tentacles and long white, spiral-shaped, oral arms. It has light sensing organs called ocelli. 

Continue reading “Pacific Sea Nettle”

Purple-Striped Jellyfish

The Purple-Striped Jellyfish (Chrysaora colorata) is a soft-bodied invertebrate marine (saltwater) animal. An invertebrate is an animal with no bones. It is also known as the Purple-Striped Sea Nettle. 

The Purple-Striped Jellyfish has a translucent (see-through) bell-shaped or umbrella-shaped dome body with purple stripes. It has long tentacles (limbs) with eight long dark purple arms and four ‘frilly’ arms. It has no brain, no heart, no blood, no bones, no excretory system, and no gills or lungs. It has nerve receptors in its body that enables it to detect smell, light, pressure, and touch. It is about 98% water.

Continue reading “Purple-Striped Jellyfish”

Plankton Star Jellyfish

The Plankton Star Jellyfish (Oceania sp.) is a soft-bodied invertebrate marine (saltwater) plankton animal. An invertebrate is an animal with no bones. It is related to the Turritiopsis. 

The Plankton Star Jellyfish is translucent (see-through) with an umbrella-shaped circular dome and long tentacles (arms). It has no brain, no heart, no blood, no bones, no excretory system, and no gills or lungs. It has nerve receptors in its body that enables it to detect smell, light, pressure, and touch. 

Continue reading “Plankton Star Jellyfish”

Moon Jellyfish

The Moon Jellyfish (Aurelia aurita) is also called the Saucer Jelly. It is a marine (saltwater) simple invertebrate (animal with no bones – is is soft-bodied). It has nerve receptors in its body.

The Moon Jellyfish is translucent (see-through) with an umbrella-shaped bell and long tentacles. It has four horseshoe-shaped gonads (reproductive organs) in the top of its bell.

The bell pulsates, which enables it to move through the water. It also conserves energy by drifting with the ocean currents and tides.

Continue reading “Moon Jellyfish”

Haitian Sea Anemone

The Haitian Sea Anemone (Condylactis gigantean) is a tropical marine ball-type animal. It is also called the Giant Caribbean Sea Anemone. The Haitian Sea Anemone is found as individuals or small, loose groups, but never in colonies like coral. It is related to coral and jellyfish.

The Haitian Sea Anemone is a large columnar sessile (non-moving) animal of many colours: white, pink, orange, pale-red, or light-brown. Its body has an adhesive pedal (foot) disc, a cylindrical body, and a central mouth surrounded by 100 or more tentacles. The tentacles often have a coloured tip (such as purple or pink).

Continue reading “Haitian Sea Anemone”