Atlantic bamboo rats use vocalizations to defend resources and warn conspecifics of potential threats. Often performing vocalizations after dark, they sit on bamboo culms and thrust their head forward with each call. They remain secluded amongst the bamboo leaves, rarely exposing their position. During alarm calls, they call once and run to an area of greater cover, and continue calling for several minutes. When conspecifics hear a call, they escape to areas with greater cover and counter-call.
Communication Channels: acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Atlantic bamboo rats are naturally rare; a study in Rio Grande do Sul State reports a density of 4.28 individuals per km^2. However, due to their wide distribution and large population, Atlantic bamboo rats are listed as "least concern" on IUCN Red List of Threatened Species. Atlantic bamboo rats are locally threatened in Minas Gerais State, Brazil due to habitat destruction largely due to logging.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Information regarding potential negative economic impacts of Atlantic bamboo rats on humans has not been documented. However, bamboo rats and mole rats in the subamily Rhizomyinae are known to affect tapioca and sugarcane crops in Thailand.
Information regarding potential economic impacts of Atlantic bamboo rats on humans has not been documented.
Atlantic bamboo rats are important seed dispersers of various bamboo species. In addition, the manner by which they feed on bamboo is thought to be beneficial to the overall health of bamboo stands in which they reside. They may also be an important food source for brown capuchins, and although it has not been documented, Atlantic bamboo rats are likely host to a number of endo- and ectoparasites as well.
Ecosystem Impact: disperses seeds
Atlantic bamboo rats are specialized herbivores, feeding on bamboo shoots, stems, and leaves. They are arboreal browsers and feed predominately at night. They also feed on the shoots of young Phyllostachys species, but appear to avoid feeding on Bambusa tuldoides.
Plant Foods: leaves; wood, bark, or stems
Primary Diet: herbivore (Folivore )
Atlantic bamboo rats, Kannabateomys amblyonyx, are native to the southeastern and southern Atlantic Forest, in Brazil, eastern Paraguay and northeastern Argentina.
Biogeographic Regions: neotropical (Native )
Atlantic bamboo rats are found in moist tropical forests, particularly bamboo thickets located near water. They build arboreal nests in native giant climbing bamboo (Guadua angustifoila), as well as in introduced species of bamboo, such as several Phyllostachys spp. and Chinese bamboo (Bambusa tuldoides). Native Guadua stands are rare in southeastern and southern Brazil due to deforestation practices. However, with the introduction of Phyllostachys spp. and B. tuldoides, Atlantic bamboo rats are able to re-inhabit parts of their native range.
Habitat Regions: tropical
Terrestrial Biomes: rainforest
The average lifespan of Atlantic bamboo rats has not been documented.
Atlantic bamboo rats are large rodents, ranging in size from 230 to 347 cm long, with a long tail of 300 to 420 cm long. They weigh between 350 to 600 g. Their dorsal pelage is olive-green to brown-orange with orange ventral pelage and white patches on their throat and chest. They have a square-like snout, gray cheeks, long whiskers and white lips. Thick fur covers the base of their tail, which tapers to a small tuft of dark-brown distal hairs. They have four long digits, an elongated and broadened third and forth digit separated by a gap, and flat nails, which allow them to have a firm grip on bamboo culms. The dental formula for members of the family Echimayidae is 1/1 0/0 1/1 3/3 for a total of 20 teeth. Atlantic bamboo rats have flat-crowned cheek teeth and differ from other Dactylomys spp. by having narrow enamel ridges present on their upper cheek teeth, as well as an absence of a constricted palate. Atlantic bamboo rats are sexually dimorphic. Although coloration is similar between sexes, males are generally larger than females. However, a monogamous population inhabiting Itapuã State Park in southern Brazil showed no sexual dimorphism.
Range mass: 350 to 600 g.
Range length: 230 to 347 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Brown capuchins are thought to be potential predators of Atlantic bamboo rats. They have been observed foraging among bamboo stands and are known to eat rodents. When capuchins forage in thickets inhabited by Atlantic bamboo rats, rats quickly find shelter amongst the bases of bamboo clumps. After capuchins leave, rat carcasses with the head and thorax missing are often found at the base of bamboo stands. However, actual capture and feeding by brown capuchins on Atlantic bamboo rats has not been documented.
Known Predators:
Anti-predator Adaptations: cryptic
Direct confirmation of polygny in Atlantic bamboo rats has not been documented in the wild nor have any genetic analyses on allelic contribution from either parent been conducted in order to determine polygyny or polyandry. However, physical characteristics and social patterns associated with polygyny have been reported in Atlantic bamboo rats. For example, males are larger than females and have larger home ranges, which may overlap the home ranges of several females. Stallings et al. (1994) found that when numerous bamboo patches were located close together, males were able to obtain access to multiple females, suggesting polygyny. However, in areas with low population densities, females are restricted to small, widely-spaced home ranges, which decreases the probability of males to acquire more than one mate. Under these situations, Atlantic bamboo rats are observed to be monogamous, living in mating pairs, with no co-occurrences of same-sex adults in the same bamboo patch.
Mating System: monogamous ; polygynous
Very little is known on the general behavior of the Atlantic bamboo rat during reproduction. They breed year round, yielding between 1 and 3 young per liter, with an average of 1.7 young per litter. Olmos et al (1993) found a deceased 600 g female with two near-term fetuses, both weighing approximately 20% of the mother’s weight. This suggests that neonate Atlantic bamboo rats require large demands of food and energy from their mother.
Range number of offspring: 1 to 3.
Average number of offspring: 1.7.
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
In Itapuã State Park, Brazil, monogamous mated males showed direct parental behavior similar to that of females, including grooming, huddling, and food provisioning. Furthermore, both males and females performed indirect parental behavior, such as alarm calls and nest building. In the event of a death or disappearance to one of the parents, the surviving parent (male or female) remains with the young, indicating prolonged parental care. In patchy arboreal habitats, biparental care is advantageous for Atlantic bamboo rats, as it reduces the risks of young falling from trees and depredation when moving amongst exposed branches.
Parental Investment: male parental care ; female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)
The Atlantic bamboo rat (Kannabateomys amblyonyx), or southern bamboo rat, is a spiny rat species found in humid tropical forests in Argentina, Brazil and Paraguay. It is the only member of the genus Kannabateomys.[2]
The Atlantic bamboo rat can reach a head-and-body length of 25 cm (9.8 in) with a tail of 32 cm (12.6 in). Its weight is about 475 g (1 lb). The pelage is the typical agouti brown-to-grey colour of many rodents, grading to chestnut on the flanks. The chin and underparts are white tinged with reddish brown. The first 6 cm (2.4 in) of the tail are well-haired but the rest is sparsely haired. There is a distinct tuft of hairs at the tip. When fully grown, this bamboo rat with its long tail is unlikely to be mistaken for any other species.[3]
The genus name Kannabateomys derives from the three ancient greek words κάννα (kánna), meaning "reed, cane", βατέω (batéō), meaning "to mount", and μῦς (mûs), meaning "mouse, rat".[4][5][6]
The species name amblyonyx derives from the two ancient greek words ἀμβλύς (amblús), meaning "blunt, not sharp", and ὄνυξ (ónux), meaning "claw, fingernail".[4][5]
This species is native to South America, where its range includes southeastern Brazil, eastern Paraguay and northeastern Argentina. Typical habitat is moist forests near water with dense understorey of bamboos. It is particularly associated with the giant bamboo Guadua angustifolia, which forms thickets.[7]
The Atlantic bamboo rat is nocturnal and is highly arboreal, scrambling around in trees and bamboos, especially near water. The home range is about 1,000 m2 (1,200 sq yd). When alarmed it issues loud squeals.[3] It probably feeds on grasses, leaves, shoots, fruits and tubers.[8]
Kannabateomys is a member of the Echimyini clade of arboreal Echimyidae rodents. Its closest relatives are Dactylomys and Olallamys. These South American bamboo rats share unique features and are grouped under the informal clade name of "Dactylomyines".[9] The dactylomyines are the sister genera to Diplomys and Santamartamys. All these taxa are closely related to the genera Echimys, Phyllomys, Makalata, Pattonomys, and Toromys. In turn, these genera share phylogenetic affinities with the clade containing Lonchothrix and Mesomys, and with Isothrix.[10]
Genus-level cladogram of the Echimyini. "Dactylomyines" Kannabateomys
(Atlantic bamboo rat)
Santamartamys
(Red-crested tree-rat)
Lonchothrix
(Tuft-tailed spiny tree-rat)
K. amblyonyx is not a common species. In the state of Rio Grande do Sul in Brazil, for example, it has been recorded as having a density of just over four individuals per square kilometre. As a nocturnal animal it is seldom seen, but it has an extensive range and is presumed to have a large total population. In some places, such as in the state of Minas Gerais in Brazil, it is threatened locally by forest clearance, but other specific threats have not been identified and the International Union for Conservation of Nature has rated its conservation status as "least concern".[1]
The Atlantic bamboo rat (Kannabateomys amblyonyx), or southern bamboo rat, is a spiny rat species found in humid tropical forests in Argentina, Brazil and Paraguay. It is the only member of the genus Kannabateomys.
