(Viverricula indica, and fossa, Cryptoprocta ferox) and birds (Accipiter madagas-cariensis, Buteo brachypterus). Large Madagascar crested ibis (Lophotibis cristata), however, were present throughout the forest. On at least five different mornings, I found their feathers and bones on the forest floor in what was likely predation from a fossa. Owls and fish eagles are present (Tyto soumagnei, Tyussp., Haliaeetus vociferoides), but neither lemur made distinct vocalizations for these potential pred ators. The only potential reptilian predator is a terrestrial constrictor, Acrantophis sp. Lemurs sometimes grunted loudly upon seeing this snake, but no attacks were ever witnessed. No hunting was ever observed at Ampamelonabe. I found no evidence of hunting at any survey sites.
Broad surveys took place in smaller forests in two regions much different from Ampamelonabe (Figure 1). I examined 12 forests that extend west of Mt. d'Ambre to the Mozambique Channel, and five forests north of Mt. d'Ambre in the very dry Cap d'Ambre. All of these forests are highly disturbed, and have been subjected to extensive regional deforestation. Strong local Antankarana and Sakalava traditions have translated to a lack of local hunting, but sportsmen and nonnative inhabitants hunt, especially in the Cap d'Ambre. Although three seasons exist in this region, annual rainfall is less than one-fourth that of Ampamelonabe, rain is strictly limited to the wet season, and temperatures are much warmer than in Mt. d'Ambre. Although many rivers flow throughout the year west of Mt. d'Ambre, no rivers flow throughout the year in the Cap d'Ambre.
Forest patches in both regions are too small to depict on most maps. Most of the area is dominated by savannah grass and small bushes. Forest is often no wider than 15-100 m, and is limited to rivers and ancient lava flows from Mt. d'Ambre. Two food trees, Tamarindus indica and Mangifera indica, often dominate the existing forests. Dense Lantana camara and Mucuna sp. border the forests west of Mt. d'Ambre; these plants are more sparse in Cap d'Ambre. Overall, forest patches seem to connect with one another and with potential seasonal food resources for lemurs, including small farming communities and continuous deciduous forest. The only other lemurs I have seen in these forests are nocturnal Microcebus; few mammalian, avian, and reptilian predators live here.
During October 1989 to September 1990, Ampamelonabe was located, trails and botanical transects were established, lemur groups were censussed, reconnaissance observations were collected, and study groups were habituated. Quantitative behavioral data and biweekly botanical phenological data were collected from October 1990 to October 1991. A total of 2080 hours of data were collected. To identify individual and group patterns in resource use and social behavior I used a combination of instantaneous focal animal and scan sampling strategies every 5 minutes from dawn until dusk. The ethogram, specific variables, and details of data analysis have been described elsewhere (Freed, 1996).
Individuals within four study groups were easily recognized on the basis of physical features. Reproductive state and other critical individual descriptions were assessed easily, as all individuals were habituated quickly to the presence of humans, and both species generally spent most of their time beneath the forest canopy. Breeding occurred for both species at the end of May, near the beginning of the dry season. Offspring were born nearly 120 days later in early October, during the hot season. The last possible bout of nursing I observed occurred in the wet season, at the end of January.
Groups were small. Each group had small, distinct home ranges. Throughout the field site both species lived in highly overlapping groups that were comprised typically of 2-5 adult females, a nearly equal number of adult males, and subadults (n = 14 crowned groups; n = 13 Sanford's groups). During the study two crowned lemur groups ranged in size between 5 and 7 individuals (northern group) and 7 and 13 individuals (southern group). Sanford's lemur study groups were between 4 and 7 individuals (northern group) and 3 and 5 individuals (southern group). Home ranges of the Sanford's study groups overlapped remarkably with those of their crowned lemur counterparts. The northern groups had home ranges of 8.89 ha (Sanford's) and 15.50 ha (crowned), but the area of overlap was 8.66 ha, 97% of the Sanford's lemur group. The southern Sanford's group's home range was 7.11 ha, and the crowned lemur counterpart was 9.18 ha. The area of overlap was 6.51 ha, or 92% of the Sanford's home range. Each study group shared parts of its home range with at least six groups each of crowned lemurs and Sanford's lemurs.
Statistically significant differences in species mean values were calculated using a randomized version of a paired-comparisons t-test. The actual differences in mean percentages between crowned lemurs and Sanford's lemurs are expressed by "A0." In randomization, an estimate of statistical significance is made by having software proceed through 1000 reshufflings of the data. After each reshuffle the statistic is recalculated, and compared with the actual statistic. Results were considered statistically significant when p < 0.05 (i.e., when fewer than 50 out of 1000 iterations were greater than the actual value). To guard against Type II errors, another 5000 iterations were made when results were nearly significant (see Edgington, 1980, and Manly, 1991).
Polyspecific associations occurred when groups of both species: stayed within 20 m of one another for more than 20 minutes; and when they routinely communicated and conducted activities with one another as if one group. Each time a group approached the focal group, I recorded the most frequent behavior and forest level of the approaching group. Quantitative data on intergroup interactions were also collected every 5 minutes. For each group (other than the focal animal's group) within 20 m of the focal animal, the name of the group and its distance from the focal animal were recorded. If a member of another group was within 10 m of the focal animal, the name and the activity of that individual were recorded. A subjective scale was used to describe the relative distance between the focal animal and the closest member of another group. All occurrences of ago-nism involving the focal animal were recorded. The duration of each intergroup interaction was the difference between the first and final 5-minute observation intervals in which the two groups associated.
Dry forest surveys were conducted in the dry season, June 2004 to August 2004. During the first 2 weeks, surveys were conducted as part of a larger interdisciplinary team investigating deforestation in northern Madagascar. The purpose of these surveys was to identify lemur populations and biogeography of this largely unexplored region. Local guides who had received training through Madagascar's regional ANGAP bureau served as translators with local people. Observations were made of all primates within 25 m of survey paths. Surveys were conducted silently at a pace of 1 km/hr. The following data were collected whenever primates were found: descriptions of the habitat; an estimate of visibility; the number of individuals of different sexes and age classes; the forest level, height, and activity of each individual; and the individual's reaction to the presence of humans. Each group was observed for 10 minutes to ensure that most group members were found, and to evaluate their reaction to the presence of humans. Dominant plant species in each forest level were recorded for each forest edge, midpoint in the forest, and each location in which lemurs were found.
Data also were collected on lemurs that were heard, but unseen. As both species routinely give distinct vocalizations shortly before dusk, 90-minute listening sessions occurred at each site. Crowned lemurs exchanged a series of piercing, shrill "WAE" calls that were often followed by distinct, loud grunts. Sanford's lemurs offered loud grunts as well, but also gave very loud, raspy sustained calls. During these sessions three people listened and recorded the location from which vocalizations originated. Groups were said to be present when all three individuals heard the same vocalizations from the same locations. Locations of nocturnal vocalizations were also recorded. Data of unseen, but otherwise located groups were recorded when these groups could not have been found where groups had been previously identified.
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