The niche of the potto,Perodicticus potto

Some new field observations on West African pottos are presented and compared with previously published information on substrate use and diet. This evidence suggests that the predominant means by which pottos find food is by carefully searching branches in the forest canopy with their noses and that gums and slow-moving invertebrates found on branch surfaces are major components of their diet. When fruits are scarce, gums may be the potto’s chief source of energy. It is argued that the potto’s deliberate locomotion and some of its anatomical peculiarities are related primarily to this diet and foraging behavior, rather than to concealment from predators or the capture of birds, two factors previously suggested to have been important in the evolution of the potto’s locomotor technique. The potto’s niche is compared to that of other lorisid primates and is found to resemble closely that of Galago crassicaudatusin several respects.     

Social organization of the Milne-Edward's potto

Nocturnal prosimian primates are often seen alone during their nocturnal activities, and are therefore categorized as "solitary". Recent research has shown that these animals actually possess social networks that differ among species. Here we present new information on one of the lesser studied prosimian primates, the potto, derived from fieldwork in Cameroon that employed radiotelemetry and behavioral observations. An analysis of association patterns and home-range overlaps between animals revealed that pottos associated more frequently with conspecifics than expected for a supposedly solitary primate. Certain males and females that were seen together regularly throughout the study, but were not observed to have contact with other pottos of the opposite sex, were labeled as "pairs". These pairs were found to have higher levels of association with each other than with other conspecifics. The only affiliative and sexual behaviors observed between members of the opposite sex occurred within the pairs of pottos. Although given the secretive nature of these primates, the possibility of extrapair copulations cannot be ruled out, their relatively small testis size indicates that sperm competition is not so important for this species.     

Nuchal adaptations inPerodicticus potto

Anatomical and behavioural evidence is put forward that supports the view that the spines of the neck of the potto are not used for abrasive or aggressive purposes but are part of a very sensitive tactile zone. It is claimed that the nuchal region is probably a tactile focus for peaceable interactions in this species.     

Electroretinogram in the nocturnal Prosimian Perodicticus potto]

There is histological evidence for the presence of cones in potto's retina: about 1 cone for 300 rods. The ERG of the dark adapted animal resembles that of the night monkey. In the potto's retina some red sensitive elements respond to wavelenghts beyond those which affect visual purple. The ERG evoked by these long wavelenghts differs from that produced by white light, suggesting a duplex character of the retina. These red sensitive receptors dark adapt faster than the others. However their fusion frequency is low, if compared with that in other species with a duplex retina. Nevertheless in potto the critical fusion frequency is higher for red light than for blue light.     

Sensory projections to the cerebral cortex inPerodicticus potto edwarsi Bouvier

The cortical sensory projections of somatic, auditory, and visual origin have been mapped in the chloralosed potto. The pathways of the contralateral side of the body project in a classical somatotopic fashion to a large area SI, behind the motor cortex and the central sulcus. The latter constitutes the posterior boundary of the motor cortex only in its ventral part. In its middle zone the motor cortex extends to its posterior lip. Above the sulcus the motor zone is immediately adjacent to the preparietal area. Visual evoked potentials are recorded behind the transverse occipital sulcus with a maximal focus just caudal to an occipital dimple. The auditory area is situated between the sylvian and parallel sulci. No heterosensory potentials (visual or auditory) can be recorded from the somatomotor area, nor from any other part outside their primary projection area. An area of convergent somatic projection devoid of somatotopic organization is found between SI and the auditory zone and another one in front of the central sulcus. In view of the poor cortical heterosensory integration, the sensory projection system of the potto seems to be less developed than in the cat.     

A duplex retina and the electroretinogram in the nocturnal Perodicticus potto.

The presence of cones in potto's retina has been proved beyond doubt although they are very restricted in number (1 cone for 300 rods). Morphologically, speaking there is no point in calling these cones "rudimentary" except for their slender outer segment. There are red sensitive elements in that retina at wavelengths beyond the spectral sensitivity of visual purple and it is tempting to assume that these elements are cones. The ERG evoked from these elements by red light differs from that in response to white and blue light. They dark-adapt faster than the receptors sensitive to blue and white flashes. However in some of their properties, for example fusion frequency, these cones behave like rods in other species. As these few cones seem to activate the bipolar cells nearly as effectively as the numerous rods, it is suggested that these cones may be responsible for day vision in the potto.     

Adrenosympathetic system and thermoregulation in a prosimian Perodicticus potto]

The urinary excretion of catecholamines in Perodicticus potto (1.76-2.94 mug/kg 24 h) is in the same range as in other mammals and the activity of the adrenosympathetic system does not account for the low metabolic rate in this species. The adrenals contain 1.140 +/- 0.14 mug A + NA/mg fresh tissue, of which adrenaline constitutes 94.5 per cent and are thus practically identical to those in Macaca irus. In a cold environment the daily urinary excretion of catecholamines of the tropical but cold hardy potto is only moderately increased.     

Dopamine of the caudate nucleus in Perodictious potto, Macaca mulatta and Macaca fascicularis]

The dopamine, dopac and tyrosinehydroxylase contents of the caudate nucleus in the prosimian Perodicticus potto and in the simii Macaca mulatta and M. fascicularis have been estimated. The results do not support the hypothesis according to which the sluggishness of the potto is somehow related to a low dopamine content of part of the extrapyramidal system as found in the Parkinson-syndrome.     

Behavioral changes in pottos (Perodicticus potto): Effects of naturalizing an exhibit

Observations of the potto (Perodicticus potto),a nocturnal prosimian primate,indicated a limited behavioral repertoire and prompted renovation of their exhibit at the Frankin Park Zoo (Boston, MA). We used the natural history of this species to direct the exhibit modifications, which used only nonsynthetic items. We added live plants, soil, bamboo, shelf fungi, grapevines, a hollow tree, and a log containing an insect dispenser to the exhibit at little expense. They provided new textures, odors, pathways, stimulation and cover for this secretive species. The changes produced a heightened aesthetic appeal to the nocturnal exhibit and improved its educational value by representing the animals’ habitat more accurately. The exhibit modifications also resulted in a significant increase in activity, an expansion of the pottos’ behavioral repertoire,the emergence of sexual behaviors, and an increased visibility to the public.     

A twenty-five-year chronicle of a group of captive nocturnal prosimians (Perodicticus potto)

Four Perodicticus potto survived captivity from 4 to 24-6 years. The male that died on 16th July 1984 was sexually mature at the time of his capture in December 1959, and thus is believed to have been slightly older than 26 years at the time of his death. These data suggest a longer life span for this species than has previously been recorded in the published literature, and do not conform well with information from other terrestrial mammals, showing a general trend of increasing longevity with increasing size (length). A 25-year record of these four animals is summarized, with an emphasis on demographic, behavioural and medical observations.     

A myeloliposarcoma in a female Perodicticus potto: mineralogical and elemental chemical analysis.

A spherical mass on the medial aspect of the thigh and caudal abdomen of a 15-year-old female Perodicticus potto was surgically removed and shown to be a myeloliposarcoma. Mineralogical examination of these tissues showed them to be amorphous to X-rays. Thirty-two elements were determined by chemical analysis of the tumor.     

Life span in captive nocturnal prosimians (Perodicticus potto) with reproductive and mortality records

Three pottos survived captivity 4 to 19 years. The female that died recently was probably 21 years old at the time of her death since she was at least primiparous at the time of her capture in December 1959. During her captive lifetime she had given birth to three single individuals and one set of twins. Her mate is still alive and is believed to be at least 20 years old, having survived 19 years of captivity. Regular copulatory behavior was noted within one month of her death. These data suggest a somewhat longer life span for this species than had been previous recorded in the scientific literature.