JAGUAR: EVOLUTION, CHARACTERISTICS, HABITAT, REPRODUCTION - BIOLOGY - 2024

The jaguar, yaguar or yaguareté (Panthera onca) is a placental mammal belonging to the Felidae family. It is the largest feline that naturally inhabits various regions in the north, center and south of the American continent.

They have an impressive fur, formed by large black rosettes, which contain dark spots inside. These stand out against a lighter golden brown background on the lower body.

Source: pixabay.com

Its habitat is the tropical humid forest, where there are streams or lagoons. Due to the degradation that the environment has suffered, the jaguar population has decreased notably. This has caused the IUCN to categorize it as a specimen that is close to being vulnerable to extinction.

The muscular body of the jaguar makes it a very strong animal. In this way it can hunt large ungulates, dragging its heavy body for long distances. Thus, they hide it from other predators, so that its food is not taken from it.

The Panthera onca has the ability to leap, which it does at great length, both upward and forward. In this way, they can suddenly knock down their prey or suddenly escape from their predator.

Evolution

The Felidae family is made up of the jaguar, leopard, tiger, lion, and snow leopard. Molecular data show that this group originated in the late Eocene. The earliest fossil records are associated with Proailurus, and possibly Stenogale and Haplogale.

The phylogenetic study of fossils allows them to be grouped into eight different clades. The first to be divided was the genus Panthera (Panthera and Neofelis). The subspecies Panthera onca, Panthera leo, and Panthera pardus are believed to have split from other Pantherinae around 8 million years ago.

The evolutionary relationship between the jaguar and the other members of the Pantherinae subfamily has different approaches. A DNA analysis suggests that the jaguar and the lion are related to each other, forming a monophyletic group.

On the other hand, an ethological and morphological analysis suggests that the leopard and the lion are the species that are closely related.

The subspecies Panthera onca has a rich fossil record. It is thought to have evolved in Eurasia and to have crossed the Bering land bridge during the early Pleistocene, to be widely distributed throughout the Old and New World.

The jaguar in America

The oldest fossil records of the jaguar in North America have been found in California, where they inhabited in the middle Pleistocene period. In South America, the ancestor of this animal corresponds to the late early or middle Pleistocene.

In Pleistocene times, Panthera onca was 20% larger than the modern species. Its front and rear legs and teeth were longer. This could be due to the evolutionary trend towards a smaller size, possibly as an effect of the geographic latitude of the habitat.

The primitive jaguars of North America were located to the north of the continent, which could explain their greater body dimensions, compared with those that settled in South America.

Recent research

The big cats belonging to the genus Panthera have a very recent evolutionary history, so it is little known.

Because of this, chromosomal studies of the jaguar (Panthera onca) and the leopard (Panthera pardus) were carried out, which were compared with the other existing Panthera species.

The results yielded evidence of positive natural selection, affecting genes related to limb development and craniofacial structure. Furthermore, pigmentation, hypoxia, and protein metabolism are also linked to each other.

These results reflect an interaction between divergence, natural selection and the union between species after speciation. All this contextualized in a successful adaptive radiation.

Danger of extinction

Due to the population decline of the jaguar, since 2002 it has been on the red list of threatened species, as a specimen very close to being vulnerable to extinction.

This categorization was carried out by the International Union for the Conservation of Nature, an international body made up of some sovereign States, civil organizations and government agencies that fight for the well-being of all the biological elements that make up nature.

-Causes

Habitat destruction

One of the fundamental elements within the habitat of the jaguar are lakes or rivers. These have decreased their channel, becoming completely dry, due to deforestation and the settlement of humans around these bodies of water.

The main threat in the decline of the jaguar population is the erosion of the environment where it develops. In this way the range of its natural ecological niche is notably reduced.

Conflicts with humans

Panthera onca has had to adapt to new environments, due to the scarcity of prey to feed on. This results in the jaguars trying to kill the pigs and cows that are in the populations close to where they are.

To defend the cattle, the villagers who raise these animals often hunt and kill the jaguar.

Poaching

Contradictorily, the fact that this species is threatened with extinction seems to make it more attractive to hunters. This is because their skin is traded on the black market in untold numbers.

In addition to the skin, its fangs are marketed, which are used in the Asian continent as components of medicines, used in natural medicine.

-Evaluation of the probability of survival

Studies have been conducted that divide the jaguar into different geographic areas depending on its life expectancy.

High probability

In the following regions the jaguar has a high percentage of possibilities to persist in the long term: the tropical humid forests of Mesoamerica (the Maya Forest of Guatemala, Belize and Mexico), the tropical forest of the Amazon basin, a strip of the Choco- Darien of Panama and Colombia, and the nearby areas of the Pantanal and the Gran Chaco.

Medium probability

The areas close to those evaluated as having a high possibility of survival are considered with a medium range so that the jaguar can develop freely.

These regions are made up of the Colombian and Venezuelan plains, the northern Caribbean coast of Panama and Colombia, southern Mexico, the highlands of Panama and Costa Rica, and the Sierras de Madre Oriental and Taumalipas in Mexico.

Low probability

These regions are the ones that should be urgently considered for the conservation of this species.

These areas include the Atlantic Tropical Forest, northern Argentina, the Cerrado of Brazil, the territory of the Great Savannah in Venezuela and Brazil, some areas of the coastal forest of Venezuela, and some populations of Mexico and Central America.

-Actions for conservation

The jaguar is protected nationally in most of the countries where it is distributed. Its hunting is prohibited in Argentina, Colombia, Brazil, Costa Rica, Honduras, French Guiana, Nicaragua, Mexico, Paraguay, Suriname, Panama, Venezuela and North America.

In Mexico, Honduras, Panama and Brazil national plans have been developed for the protection of the species.

Due to the fragmentation of their habitat, there is a proposal to establish a continuous protection strip from North America to South America, covering the ranges of the jaguar's habitat.

However, efforts to preserve this group of big cats have not borne the expected results, as threats to this specimen still persist today.

General characteristics

Size

The body weight of Panthera onca can vary markedly depending on the subspecies. Animals that live farther from the equator could be larger. This variation is possibly associated with the availability of very bulky prey in the place where they live.

The length of his body can be between 112 and 241 centimeters. However, its tail, compared to the rest of the body, is short, reaching a maximum of 75 centimeters. In the jaguar there is sexual dimorphism, females could be up to 20% smaller than males.

The largest specimens are in open areas such as the open floodplains, the Brazilian Pantanal, and the Venezuelan plains. There, on average, the females weigh about 76 kg and the males about 100 kg.

The smallest species are found in very dense areas, such as the forests of Central America and the Amazon. The females of these regions reach 42 kg and the males 57 kg.

Fur

Their skin is covered with short hairs in shades between brown and light yellow or reddish brown. On this stand out some rosettes of dark color, round in shape with a yellow or intense brown center. These spots could vary in the same animal or between members of the same species.

Those on the head and neck are more solid in color, as well as on the tail, where they could join and form a single band. The ventral region, the internal areas of its legs and the lower flanks are white.

At birth, some jaguars may have dark or black hair. Also, although it is very rare, they could be born white.

Head

Its head is rounded, robust and large. Their eyes are round and large, with the irises in a reddish or yellowish-red hue. Since these are in front of the face, your vision is binocular.

In addition, they can see in the dark, thanks to the presence of a reflective-type membrane that helps to concentrate light rays within the focal field of the retina. This is extremely useful for viewing prey or any threat at a considerable distance.

The sense of smell is highly developed, being able to catch the scent of its adversaries or its prey even if they are quite far from them.

It has powerful jaws that contribute to its bite being one of the most powerful of all big cats.

Torso

The body of this animal is adapted to use power and force, rather than speed. Because of this, its body build is short, muscular and compact, allowing it to swim and climb substrates with great ease .

Extremities

They have short, thick and very powerful legs, due to their extremely strong musculature. Its claws are sharp and retractable.

Teeth

In the mouth of Panthera onca the canines stand out, which are sharp and long. These are used to pierce the bones of their prey and break very hard surfaces.

The sharp premolars work like scissors, allowing them to cut the meat into chunks. They can also crush the bone to eat the marrow that is inside.

The incisors are flat and small. These characteristics make it easier for them to scrape off the small pieces of meat that may have been attached to the bone of the prey.

Taxonomy and subspecies

Animal Kingdom.

Subkingdom Bilateria.

Chordate Phylum.

Vertebrate Subfilum.

Tetrapoda superclass.

Mammal class.

Subclass Theria.

Infraclass Eutheria.

Order Carnivora.

Felidae family.

Subfamily Pantherinae.

Genus Panthera.

Species Panthera onca

Source: pixabay.com redesigned by Johanna Caraballo

The black jaguar

Within the population of these big cats, black coloration can occur throughout their fur. Although this does not happen very often, black jaguars are impressive. This is due to a melanistic condition of the Panthera onca species.

The various variations in the coloration of the skin of animals have drawn the attention of evolutionary biologists. Among pigmentary polymorphisms, melanism is present in several organisms.

In the jaguar, the black coloration of its skin is caused by dominant and recessive mutations in the MC1R and ASIP genes, respectively.

Melanism and habitat

The frequency of melanism in the jaguar is approximately 10%. In studies of this condition, black jaguars have been observed to be absent from open and periodically mature habitats.

An example of these regions are the savannas and grasslands of the Colombian and Venezuelan plains and in Pantanal, in Brazil. The largest number of black jaguars has been found in South America, specifically in Brazil, Peru and Ecuador.

Specialists suggest that these findings could be related to environmental factors, such as temperature and humidity.

The results of the investigations support the hypothesis that the distribution of the melanism allele in Panthera onca, with a particular regional frequency, is influenced by two factors.

One of them, at least partially, is natural selection, and the other is the environmental characteristics of the habitat.

Habitat and distribution

The habitat of the jaguar is characterized by a dense forest, mainly primary and secondary forests, by the existence of constant sources of water and prey to feed.

Despite these very specific needs, they can be found in a great diversity of ecosystems, such as rainforests, pampas grasslands, swampy areas, seasonally flooded areas, dry deciduous forests and thorn scrub.

They may also live in lowland tropical forests, tropical or dry forests, lowland arable grasslands, and xeric habitats. Although they have occasionally been seen in territories with elevations of up to 3,000 meters, they are generally not found above 2,700 meters.

The habitat of this specimen is strongly associated with the need for the presence of rivers, lakes or streams. For this reason they are more concentrated in the humid tropical forests than in the deciduous forests.

Even within the same area, they can be easily found in the vicinity of water resources. This characteristic of the species places it directly in conflict with farmers, since they also need access to water sources.

Distribution range

Panthera onca is widely distributed throughout the American continent. Throughout history, this feline was located from North America to Argentina, covering various regions of Central and South America.

However, at present, the population is fragmented, disappearing from large areas of North America, Brazil, Mexico, Uruguay, El Salvador and the Argentine pampas.

Its current area is estimated at a total of 8.75 million km2, about 46% less than it originally had.

It is distributed in the following countries: Argentina, Belize, Bolivia, Brazil, Colombia, Guatemala, Ecuador, Costa Rica, Guyana, Honduras, French Guiana, Mexico, Paraguay, Nicaragua, Suriname, Panama, Venezuela, Peru, and the United States. Only a few species remain in the latter country.

Although the regions with the highest density of jaguars are South and Central America, they are mostly concentrated in the Brazilian Amazon.

Reproduction

Females are estimated to reach sexual maturity at 14 or 24 months. Males are mature between 24 and 36 months. The jaguar has courtship behaviors; females in heat move in and out of their territory making sounds that announce to the male that he is ready to mate.

The males respond with vocalizations in different tones and intensities, later going to the place where the female is. Very often the males confront each other for a chance to copulate with the female.

The jaguar's mating system is polygynous. However, after mating, especially after their young have been born, females do not tolerate the presence of males.

The estrous cycle is 37 days, where the estrus could last between 6 and 17 days. This is generally accompanied by changes in behavior, such as vocalizations and increased scent marks on the territory.

The jaguar can mate at any time of the year, although it is usually more frequent in the months of December to March. Gestation could last between 90 and 110 days, giving birth to a maximum of four young at each birth.

Feeding

Panthera onca is a carnivorous species. More than 85 different species of animals are recorded in its diet, including birds, reptiles and mammals. Some of the preferred prey are alligators, snakes, turtles, capybaras, porcupines, large birds, and fish.

However, they prefer large ungulates. This could be associated with the fact that it saves energy, since with a large prey it could feed for up to four days, avoiding having to go hunting during that time.

The jaguar has a variable diet, adjusted to the ease of capture of the prey and the availability of the same. At present, due to the decrease in wild prey, this animal is forced to consume the livestock found on farms close to its habitat.

They are opportunistic hunters. They hide and when they visualize their prey, they suddenly jump on them. They could also give you a strong bite directly on the neck, and then suffocate them.

Another method is to kill them immediately, piercing the back of the skull with their strong canines. The powerful jaws, in conjunction with its canines, allow it to penetrate both the thick skin of a reptile and the shell of a tortoise.

Behavior

Social

The jaguar is a solitary animal, except for the mating season. The male aggressively protects his territory and the females that are in it.

These animals are great lovers of water. They usually rest on the bank of the river or enter it to hunt some fish typical of the area.

The jaguar has periods of maximum activity, due to its own hunting habits. For this reason, it is often put into the water to swim. Their body is adapted so that they are excellent swimmers.

This behavior may be intended to cool you down and thus cool your body, thereby reducing your body temperature.

They can be active at any time of the day, although they prefer to be around sunrise or sunset. While resting, they lie under thick vegetation, a large shade, or in a cave.

Also, at the time of the floods, they could climb the branches of the trees and stay there for a long time.

Marking

Jaguars mark their territory with chemical marking. For this they urinate and defecate in prominent places on the ground.

However, the most common marks are scratches on the floor. These are carried out with their strong legs and claws. Groups of scratches can often be seen on the same path, slightly separated from each other.

This could indicate that these landmarks are responses to other jaguars in the same area.

Communication

This group of felines communicates with their peers through various vocalizations, among which is the roar. Another sound is growling, which can vary in pitch, frequency, and power.

They even have specific modulations if they are emitted by a male or a female. The vocalizations of the males are guttural and hoarse, whereas those of the females are soft. The exception to this is when the female makes 7 loud sounds to warn the male that she wishes to mate.

References

1. Florida Museum (2018). Panthera onca. University of Florida. Recovered from floridamuseum.ufl.edu
2. Blake Flournoy (2018). Why Are Jaguars Endangered Animals ?. Sincencing. Recovered from sciencing.com.
3. Emura S, Okumura T, Chen H (2013). Morphology of the lingual papillae in the jaguar. NCBI. Recovered from ncbi.nlm.nih.gov
4. Henrique V. Figueiró, Gang Li, Fernanda J. Trindade, Juliana Assis, Fabiano Pais, Gabriel Fernandes, Sarah HD Santos, Graham M. Hughes, Aleksey Komissarov, Agostinho Antunes, Cristine S. Trinca, Maíra R. Rodrigues, Tyler Linderoth, Ke Bi, Leandro Silveira, Fernando CC Azevedo, Daniel Kantek, Emiliano Ramalho, Ricardo A. Brassaloti, Priscilla MS Villela, Adauto LV Nunes, Rodrigo HF Teixeira, Ronaldo G. Morato, Damian Loska, Patricia Saragüeta, Toni Gabaldón, Emma C. Teeling, Stephen J. O'Brien, Rasmus Nielsen, Luiz L. Coutinho, Guilherme Oliveira, William J. Murphy †, Eduardo Eizirik † (2017). Genome-wide signatures of complex introgression and adaptive evolution in the big cats. Science Advances. Recovered from advances.sciencemag.org
5. Werdelin, Lars & Yamaguchi, Nobuyuki & Johnson, Warren & O'Brien, SJ. (2010). Phylogeny and evolution of cats (Felidae). Research gate. Recovered from researchgate.net.
6. Quigley, H., Foster, R., Petracca, L., Payan, E., Salom, R. & Harmsen, B. (2017). Panthera onca. The IUCN Red List of Threatened Species. Recovered from iucnredlist.org.
7. ITIS (2018). Panthera onca. Recovered from itis.gov.
8. Defenders of wildlife (2018). Jaguar. Recovered from defenders.org.
9. Feline worlds (2018). Jaguar, habitat and distribution. Recovered from felineworlds.com.
10. Nogueira, J. (2009). Panthera onca. Animal Diversity Web. Recovered from animaldiversity.org.
11. Feline worlds (2018). Jaguar anatomy. Recovered from felineworlds.com.
12. Bart J. Harmsen Rebecca J. Foster Said M. Gutierrez Silverio Y. Marin C. Patrick Doncaster (2010). Scrape-marking behavior of jaguars (Panthera onca) and pumas (Puma concolor). Oxford academic. Recovered from academic.oup.com.
13. Lucas Gonçalves da Silva (2017). Ecology and Evolution of in Big Cats Case Study with Black Leopards and Jaguars. Research gate. Recovered from researchgate.net.