Post by Vodmeister on Sept 9, 2013 5:00:51 GMT 5
Colossal Squid
The colossal squid (Mesonychoteuthis hamiltoni), sometimes called the Antarctic or giant cranch squid, is believed to be the largest squid species in terms of mass. It is the only known member of the genus Mesonychoteuthis. It is known from only a few specimens, and current estimates put its maximum size at 12–14 m (39–46 ft) long, based on analysis of smaller and immature specimens, making it the largest known invertebrate. The heaviest colossal squid weighed 495 kg (1,091 lb).
Little is known about the life of this creature, but it is believed to feed on prey such as chaetognatha, large fish such as the Patagonian toothfish, and other squid in the deep ocean using bioluminescence. The colossal squid is thought to have a slow metabolic rate, needing only around 30 grams (1.1 oz) of prey daily.
Estimates of its energetic demands suggest it is a slow-moving ambush predator, using its large eyes primarily for predator detection rather than active hunting.
Based on capture depths of a few specimens, and beaks found in sperm whale stomachs, the adult colossal squid ranges at least to a depth of 2.2 km (7,200 ft), and juveniles can go as deep as 1 km (3,300 ft). It is believed to be sexually dimorphic, with mature females generally being much larger than mature males, as is common in many species of invertebrates.
The squid's method of reproduction has not been observed, although some data on their reproduction can be inferred from anatomy. Since males lack an organ called a hectocotylus (an arm used in other cephalopods to transfer a spermatophore to the female), they probably use a penis instead, which would be used to directly implant sperm into females.
Many sperm whales carry scars on their backs believed to be caused by the hooks of colossal squid. Colossal squid are a major prey item for Antarctic sperm whales feeding in the Southern Ocean; 14% of the squid beaks found in the stomachs of these sperm whales are those of the colossal squid, which indicates colossal squid make up 77% of the biomass consumed by these whales. Many other animals also feed on this squid, including beaked whales (such as the southern bottlenose whale), pilot whales, southern elephant seals, Patagonian toothfish, sleeper sharks (Somniosus antarcticus), and albatrosses (e.g., the wandering and sooty albatrosses). However, beaks from mature adults have only been recovered from those animals large enough to take such prey (i.e. sperm whales and sleeper sharks), while the remaining predators are limited to eating juveniles or young adults.
Saltwater Crocodile
The saltwater crocodile (Crocodylus porosus), also known as saltie, estuarine or Indo-Pacific crocodile, is the largest of all living reptiles, as well as the largest terrestrial and riparian predator in the world. The males of this species can reach sizes of up to 7 m (23 ft) and weigh as much as 2,000 kg (4,400 lb). However, an adult male saltwater crocodile is generally around 4.9 m (16 ft) in length and weighs 400-1,000 kg (880-2,200 lb), rarely growing significantly larger. Females are much smaller and often do not surpass 3 m (9.8 ft). As its name implies, this crocodile can live in salt water, but usually resides in mangrove swamps, estuaries, deltas, lagoons, and lower stretches of rivers. They have the broadest distribution of any modern crocodile, ranging from the eastern coast of India, throughout most of Southeast Asia, stretching south to northern Australia, and historically ranging as far west as off the eastern coast of Africa and as far east as waters off the coast of Japan.
The saltwater crocodile is a formidable, opportunistic, and adaptable predator capable of taking almost any animal that enters its territory. It is an apex predator which preys on a variety of fish, crustaceans, reptiles, birds and mammals, including other predators. It is an ambush predator, waiting for a suitable moment to attack. It has the strongest bite of any animal today, but its teeth are not designed to rip flesh, but to hold onto the prey item, which is an advantage that reduces the animal's chance of escape. These two properties allow the crocodile to catch and drag the animal into the water with the minimal possibility of losing its prey. Then, the prey item is swallowed whole or torn into pieces either by death roll or by sudden jerks of the head. Saltwater crocodiles are considered as the most dangerous species of crocodiles to humans, although attacks and killing are rare.
Saltwater crocodiles are more territorial than other crocodilians, and are less tolerant of their own kind. Most crocodiles are social animals, sharing basking spots and food. Saltwater crocodiles do not fall into this category however, especially in the case of adult males of the species. They are extremely territorial and will fight off any intruders. The adult male will share his territory with a female. Saltwater crocodiles mate in the wet season, laying eggs in a nest made into a mound of mud and vegetation. The female guards the nest and hatchlings from predators. Conservation efforts were successful in this species, and it has recovered since the 1970s. Today, they aren't endangered in many countries. However, some populations are still at risk.
The colossal squid (Mesonychoteuthis hamiltoni), sometimes called the Antarctic or giant cranch squid, is believed to be the largest squid species in terms of mass. It is the only known member of the genus Mesonychoteuthis. It is known from only a few specimens, and current estimates put its maximum size at 12–14 m (39–46 ft) long, based on analysis of smaller and immature specimens, making it the largest known invertebrate. The heaviest colossal squid weighed 495 kg (1,091 lb).
Little is known about the life of this creature, but it is believed to feed on prey such as chaetognatha, large fish such as the Patagonian toothfish, and other squid in the deep ocean using bioluminescence. The colossal squid is thought to have a slow metabolic rate, needing only around 30 grams (1.1 oz) of prey daily.
Estimates of its energetic demands suggest it is a slow-moving ambush predator, using its large eyes primarily for predator detection rather than active hunting.
Based on capture depths of a few specimens, and beaks found in sperm whale stomachs, the adult colossal squid ranges at least to a depth of 2.2 km (7,200 ft), and juveniles can go as deep as 1 km (3,300 ft). It is believed to be sexually dimorphic, with mature females generally being much larger than mature males, as is common in many species of invertebrates.
The squid's method of reproduction has not been observed, although some data on their reproduction can be inferred from anatomy. Since males lack an organ called a hectocotylus (an arm used in other cephalopods to transfer a spermatophore to the female), they probably use a penis instead, which would be used to directly implant sperm into females.
Many sperm whales carry scars on their backs believed to be caused by the hooks of colossal squid. Colossal squid are a major prey item for Antarctic sperm whales feeding in the Southern Ocean; 14% of the squid beaks found in the stomachs of these sperm whales are those of the colossal squid, which indicates colossal squid make up 77% of the biomass consumed by these whales. Many other animals also feed on this squid, including beaked whales (such as the southern bottlenose whale), pilot whales, southern elephant seals, Patagonian toothfish, sleeper sharks (Somniosus antarcticus), and albatrosses (e.g., the wandering and sooty albatrosses). However, beaks from mature adults have only been recovered from those animals large enough to take such prey (i.e. sperm whales and sleeper sharks), while the remaining predators are limited to eating juveniles or young adults.
Saltwater Crocodile
The saltwater crocodile (Crocodylus porosus), also known as saltie, estuarine or Indo-Pacific crocodile, is the largest of all living reptiles, as well as the largest terrestrial and riparian predator in the world. The males of this species can reach sizes of up to 7 m (23 ft) and weigh as much as 2,000 kg (4,400 lb). However, an adult male saltwater crocodile is generally around 4.9 m (16 ft) in length and weighs 400-1,000 kg (880-2,200 lb), rarely growing significantly larger. Females are much smaller and often do not surpass 3 m (9.8 ft). As its name implies, this crocodile can live in salt water, but usually resides in mangrove swamps, estuaries, deltas, lagoons, and lower stretches of rivers. They have the broadest distribution of any modern crocodile, ranging from the eastern coast of India, throughout most of Southeast Asia, stretching south to northern Australia, and historically ranging as far west as off the eastern coast of Africa and as far east as waters off the coast of Japan.
The saltwater crocodile is a formidable, opportunistic, and adaptable predator capable of taking almost any animal that enters its territory. It is an apex predator which preys on a variety of fish, crustaceans, reptiles, birds and mammals, including other predators. It is an ambush predator, waiting for a suitable moment to attack. It has the strongest bite of any animal today, but its teeth are not designed to rip flesh, but to hold onto the prey item, which is an advantage that reduces the animal's chance of escape. These two properties allow the crocodile to catch and drag the animal into the water with the minimal possibility of losing its prey. Then, the prey item is swallowed whole or torn into pieces either by death roll or by sudden jerks of the head. Saltwater crocodiles are considered as the most dangerous species of crocodiles to humans, although attacks and killing are rare.
Saltwater crocodiles are more territorial than other crocodilians, and are less tolerant of their own kind. Most crocodiles are social animals, sharing basking spots and food. Saltwater crocodiles do not fall into this category however, especially in the case of adult males of the species. They are extremely territorial and will fight off any intruders. The adult male will share his territory with a female. Saltwater crocodiles mate in the wet season, laying eggs in a nest made into a mound of mud and vegetation. The female guards the nest and hatchlings from predators. Conservation efforts were successful in this species, and it has recovered since the 1970s. Today, they aren't endangered in many countries. However, some populations are still at risk.
