Чёрный ревун: экология, поведение и угрозы популяции.

Species of New World monkey
species with "black howler" in their common names

The black howler (Alouatta caraya) or black and gold howler, The black howler is distributed in areas of South America such as Paraguay, southern Brazil, eastern Bolivia, northern Argentina, and Uruguay. This species is sexually dimorphic, with adult males having entirely black fur and adult females and babies of both sexes having an overall golden colouring; which emphasizes black and gold in the name. The female, as well as infants of both sexes, have fur of a golden tone. The vocalizations of black howlers have been studied in Brazil, where they mostly vocalize around dawn. This species is mostly arboreal, rarely coming down to the ground. Their gut microbiome composition changes seasonally to accommodate dietary changes due to restrictions of resources in the environment. Their diet is not different between different sexes and ages. Usually, howler monkeys have a single dominant male, with multiple adult females and babies in smaller groups. In larger groups, the howler monkeys' group composition can vary. in 2010 examined the promiscuity of black howler females along the Paraná River in Argentina using a scan sampling technique. According to the findings, sexual solicitation of female mate choice occurred when a female actively pursued a particular male by grooming, touching, and following him, and displaying a specific posture to get the male to approach them. They may survive in a variety of settings, including disturbed ecosystems and forest remnants in agricultural regions and human populations.

From the IUCN Red List, the black howler is seen as a Near Threatened species. This is a result to population declines, habitat degradation, hunting pressure, and disease outbreak vulnerability. Anthropogenic disturbances are the top common reasons for the slow decrease of the black howler population; jeopardizing and degrading their ecosystems for residential and commercial development as well as agriculture. Hunting and the illegal pet trade are also contributing factors to the black howler's population reduction. In a 2020 study in the city of Pilar, Paraguay, examining the attitudes of humans towards urban howler monkeys, the researchers asked selected participants questions regarding hunting and pet trade of black and gold howler monkeys. In their findings, 93% of participants said they knew it was illegal to kill the monkeys, but more than half of the participants did not know it was also prohibited to keep them as pets. It was also stated in their findings that 8% of participants believe that black and gold howler monkeys had been hunted for their flesh. Black howlers are also susceptible to disease such as yellow fever. In Brazil, there have been outbreaks of sylvatic yellow fever that have resulted in significant population declines.

The interaction between people and black and gold howlers was also a topic of the research conducted by Marco Alesci et al. in 2020 in the city of Pilar, Paraguay. People interviewed for this research believed that there were many benefits to having the black howler monkeys in the urban environment such as a benefit for increasing tourism. The researchers also polled a group of people in Pilar regarding the conservation of black howlers in the area as part of their research. As a result, domestic dogs attacking black howlers in urban areas, electrocution on uninsulated power lines, and people killing the monkeys were all recognized as threats. Because the power lines are commonly utilized for transit by the black howler monkeys, three howler fatalities by electrocution were documented during the research period. As mentioned in the article, efforts for the conservation of the black howlers in Pilar are minimal, but if urbanization keeps rising, it may pose serious dangers to their existence by diminishing accessible trees and pushing howlers to walk on power wires or on the ground more.