Post by rock on Apr 24, 2019 21:39:36 GMT 5
thylacoleo
Thylacoleo ("pouch lion") is an extinct genus of carnivorous marsupials that lived in Australia from the late Pliocene to the late Pleistocene (2 million to 46 thousand years ago). Some of these "marsupial lions" were the largest mammalian predators in Australia of that time, with Thylacoleo carnifex approaching the weight of a small lion. The estimated average weight for the species ranges from 101 to 130 kg. Pound for pound, Thylacoleo carnifex had the strongest bite of any mammal species living or extinct; a T. carnifex weighing 101 kg (223 lb) had a bite comparable to that of a 250 kg African lion, and research suggests that Thylacoleo could hunt and take prey much larger than itself.[2] Larger animals that were likely prey include Diprotodon spp. and giant kangaroos. It seems improbable that Thylacoleo could achieve as high a bite force as a modern-day lion; however, this might have been possible when taking into consideration the size of its brain and skull. Carnivores usually have rather large brains when compared to herbivorous marsupials, which lessens the amount of bone that can be devoted to enhancing bite force. Thylacoleo however, is thought to have had substantially stronger muscle attachments and therefore a smaller brain. Canids possessed elongated skulls, while cats tend to possess foreshortened ones. The similarities between cat morphology and that of Thylacoleo indicates that although it was a marsupial, biologically it possessed greater similarities to cats, and as a result had a higher capacity for bite strength than other animals within its own infraclass.[3]
It also had extremely strong fore limbs, with retractable, cat-like claws, a trait previously unseen in marsupials. Thylacoleo also possessed enormous hooded claws set on large semiopposable thumbs, which were used to capture and disembowel prey. The long muscular tail was similar to that of a kangaroo. Specialised tail bones called chevrons allowed the animal to balance on its back legs, and freed the front legs for slashing and grasping.[4]
Its strong forelimbs, retracting claws, and incredibly powerful jaws mean that Thylacoleo possibly climbed trees and perhaps carried carcasses to keep the kill for itself (similar to the leopard today).[5] The climbing ability would have also helped them climb out of caves, which could therefore have been used as dens to rear their young.[6]
Due to its unique predatory morphology, scientists repeatedly claim Thylacoleo to be the most specialised mammalian carnivore of all time.[7] Thylacoleo had vertical shearing 'carnassial' cheek teeth that are relatively larger than in any other mammalian carnivore.[2] Thylacoleo was clearly derived from the diprotodontian ancestry due to its incisor morphology and is distinguished by the pronounced development of upper and lower third premolars which functioned as extreme carnassials with complementary reduction in the molar teeth row.[8] They also had canines but they served little purpose as they were stubby and not very sharp.[9]
Thylacoleo was 71 cm (28 in) at the shoulder and about 114 cm (45 in) long from head to tail. The species T. carnifex is the largest, and skulls indicate they averaged 101 to 130 kg (223 to 287 lb), and individuals reaching 124 to 160 kg (273 to 353 lb) were common, and the largest weight was of 128–164 kg (282–362 lb).[10] Fully grown, Thylacoleo carnifex would have been close to the same size as a jaguar.While considered a powerful hunter, and a fierce predator, many today would assert that due to its physiology Thylacoleo was, in fact, a slow runner, limiting its ability to chase prey. Analysis of its scapula suggests "walking and trotting, rather than climbing ... the pelvis similarly agrees with that of ambulators and cursors [walkers and runners]". "These bones indicate that Thylacoleo was a slow to medium-paced runner, which is likely to mean it was an ambush predator. That fits with the stripes: camouflage of the kind one would need for stalking and hiding in a largely forested habitat (like tigers) rather than chasing across open spaces (like lions).”[12] It may have functioned generally much like a larger analog of the Tasmanian devil.[6] New evidence also suggests that it may have been arboreal, and was at the very least capable of climbing trees.
At the site at Lancefield, many bones have been excavated and have been discovered to be a part of an estimated several hundred thousand diverse individuals. Some of those bones had strange cuts on their surfaces. Two likely explanations follow from this: marks were produced by prehistoric humans during butchering or by the teeth of Thylacoleo carnifex. Through archaeological and paleoecological findings, researchers concluded that the T. carnifex had caused all the cut marks. Because of their large size, the population had to feed on other species just as large as their own just to avoid an imbalance in their diets. They may have killed by using their front claws as either stabbing weapons or as a way to grab their prey with strangulation or suffocation.
african lioness
Living in the grasslands, scrub, and open woodlands of sub-Saharan Africa, the lion is the second largest cat in the world. It is dwarfed slightly by the tiger, which is closely related and has a very similar body type.
Unlike other cats, lions are very social animals. They live in groups, called prides, of around 30 lions. A pride consists of up to three males, a dozen related females, and their young. The size of the pride is determined by the availability of food and water. If resources are scarce, the pride becomes smaller.
Pride members keep track of one another by roaring. Both males and females have a very powerful roar that can be heard up to 8 km (5 mi.) away.
Males and females take on very different roles in the pride. Male lions spend their time guarding their territory and their cubs. They maintain the boundaries of their territory, which can be as large as 260 sq. km (100 sq. mi.), by roaring, marking it with urine, and chasing off intruders. Their thick manes, a unique trait to male lions, protect their necks when they fight with challengers.
Big male lionFemale lions are the primary hunters of the group. They are smaller and more agile than males. But since their prey is still generally faster than them, they use teamwork to bring an animal down. Fanning out, they form a semicircle, with the smaller, weaker lionesses herding the prey towards the center. Then the stronger females knock the animal down and make the kill.
Lions usually hunt at night. Their prey includes antelopes, buffaloes, zebras, young elephants, rhinos, hippos, wild hogs, crocodiles and giraffes. But they also sometimes eat smaller prey like mice, birds, hares, lizards, and tortoises. They are not above stealing kills from other carnivores, like hyenas, wild dogs, cheetahs, and leopards, or scavenging spoiled meat.
After a successful hunt, all the lions in the pride share the meal. But there is a pecking order, with the adult males taking first claim, followed by the lionesses, and finally, the cubs.
Lions have a fast-working digestive system, which allows them to gorge themselves and then go for seconds shortly after. If available, they will drink water everyday. But they can go 4-5 days without drinking by obtaining moisture from the stomach contents of their prey.
Spending 16-20 hours of the day sleeping or resting, lions are the laziest of the big cats. They can be found lying on their backs with their feet up or taking a snooze up in a tree. While lazing around, they are very affectionate towards one another, rubbing heads, grooming, and purring.
Lionesses give birth to 2-3 cubs at a time. Usually a couple females give birth around the same time. The cubs are then raised together, sometimes nursing communally.
Lioness with cubsVulnerable to predators like hyenas, leopards, and black-backed jackals, cubs have a 60-70% mortality rate. They are sometimes trampled by large animals like buffaloes. Furthermore, when another group of male lions takes over a pride, they kill all the cubs so they can sire their own with the lionesses.
Female cubs stay with the group as they age. At around two years old, they become capable hunters. But young males are forced out of the pride at that age. They form bachelor groups and follow migrating herds until they are strong enough to challenge male lions of other prides. In general, a group of males stays in power in the pride for around three years before another bachelor group takes it over.
