Northern Brown Howler (Alouatta guariba guariba)

These individuals are from Feliciano Miguel Abdala Reserve (Caratinga Biological Reserve), in northern Espirito Santo.

The northern brown howler (Alouatta guariba guariba) is the type subspecies of the brown howler, native to Brazil. It is listed as critically endangered, with fewer than 250 individuals restricted to the vicinity of the Jequitinhonha River. The species feeds on fruits, flowers, and by preference immature leaves which are easier to digest than mature leaves; foraging for these foods in hillside habitats was shown to require more energy expenditure than in valley habitats.

The northern brown howler is endemic to the Minas Gerais province of Brazil and the southern part of Bahia state. Its range extends from the Atlantic coast to the Rio Pardo and Águas Vermelhas in the north, and to the Jequitinhonha River and Virgem da Lapa to the west and south, largely delineated by the inland extent of the coastal rainforest belt. Although mainly living in the canopy of primary forest, it can adapt to secondary forest and other disturbed habitats. It may also be present in the northern part of Espírito Santo province, and appears to have had a wider range in the past.

The northern brown howler is present in several protected areas, including the Mata Escura Biological Reserve, where the critically endangered northern muriqui (Brachyteles hypoxanthus) and the endangered golden-bellied capuchin (Sapajus xanthosternos) are also found. However, this reserve is close to rural settlements and subject to illegal logging, hunting and increased incidence of wildfires. The monkey may also be present in other protected areas, but this is uncertain, because the subspecies' southern distributional limit is unclear.

Southern Brown Howler (Alouatta guariba clamitans)

The southern brown howler is a monkey subspecies of brown howler native to southeastern Brazil (Minas Gerais to Rio Grande do Sul) and far northeastern Argentina (Misiones). Gregorin, 2006, considered the southern brown howler to be a separate species, Alouatta clamitans, but this has not been universally accepted.

The southern brown howler is found in the Atlantic forests of eastern Brazil where it occurs in the states of Espírito Santo, Rio de Janeiro, Minas Gerais, São Paulo, Paraná, Santa Catarina and Rio Grande do Sul. Its range extends southwards as far as the Camaquã River and eastward to Misiones Province in Argentina. Its northern extent is unclear, but may be the Doce River or the Jequitinhonha River. Habitats include lowland, sub-montane and montane forests, and it is tolerant of disturbed habitats and human encroachment.

Howlers move around in small troops, consisting of a dominant male, several females and a number of juveniles. The monkeys are so called because of the loud calls made by males, more roar than howl, which can be heard a mile (1.5 km) or more away, mostly at dawn and dusk. The throats of males have enlarged vocal sacs and large tracheal cartilages which act as resonators to amplify the sounds. The diet of these monkeys consists mostly of leaves, supplemented by flowers and fruit, and these foods being plentiful in the rainforest, the territories defended by the troops are small. Rival troops howl at each other but territorial disputes are mostly settled vocally, without the monkeys needing to meet face to face.

In the Araucaria pine forests of southern Brazil, the chief predators of these monkeys are ocelots (Leopardus pardalis), cougars (Puma concolor), and jaguars (Panthera onca), as well as the larger birds of prey.

The International Union for Conservation of Nature has assessed this monkey's conservation status as being vulnerable. This is partly because of the monkey's susceptibility to yellow fever; during the period 2007 to 2009, an outbreak of yellow fever killed large numbers of howlers in the Misiones Province in Argentina, and the State of Rio Grande do Sul in Brazil. The animal has a wide range and is present in a number of protected areas, but the rainforest in which it lives is being cleared for cattle ranching and agriculture, resulting in fragmentation of the forest. The subpopulations in these fragments are likely to suffer from inbreeding. They are also impacted by urbanisation and are hunted for food.

The individuals below are from the Botanical Gardens in Sao Paulo.

 Southern Brown Howler (Alouatta guariba clamitans) Alfonso Claudio, Espirito Santo, Brazil