Little is known about the ecology and diet of Varanus bitatawa, a recently discovered monitor lizard endemic to the Sierra Madre Mountains of Northern Luzon. Here we present data that show that it... Show moreLittle is known about the ecology and diet of Varanus bitatawa, a recently discovered monitor lizard endemic to the Sierra Madre Mountains of Northern Luzon. Here we present data that show that it has a seasonal omnivorous diet comparable to its southern congener Varanus olivaceus. Consumption of fruits from Pandanus sp., Canarium sp. and Microcos stylocarpa was evident in fecal samples, from spool and line tracking observations, and from camera trap images. The frugivorous diet was supplemented with snails and insects belonging to the orders Orthoptera, Phasmatodea and Coleoptera. Habitat of V. bitatawa was studied in lowland disturbed dipterocarp forest at an elevation below 300 m. In three sampled sites basal area of dipterocarp trees ranged from 16.23 to 84.14 m2 ha-1, total tree density from 624.6 to 1021.4 trees per ha-1 and density of Pandanus from 115.15 to 222.30 trees per ha-1. Predominantly arboreal, V. bitatawa showed reliance on large sentinel trees. Of trees utilized, 47.4% were estimated at over 30 m tall with a mean circumference at breast height (CBH) of 176.28 cm and were significantly larger than the mean CBH of trees in sampled habitats. Shy and reclusive, V. bitatawa is likely to be vulnerable to disturbance. Illegal selective logging further degrades remaining habitat threatening the large dipterocarp trees on which they rely. Continued and improved protection of the forests within the Sierra Madre Mountain Range is imperative to safeguard the future of this restricted range species. Show less
Law, S.J.; Kort, S.R. de; Bennett, D.; Weerd, M. van 2016
The newly described Varanus bitatawa is a large, frugivorous, monitor lizard endemic to the northern Sierra Madre mountain range in Luzon, Philippines. This study presents the first description of... Show moreThe newly described Varanus bitatawa is a large, frugivorous, monitor lizard endemic to the northern Sierra Madre mountain range in Luzon, Philippines. This study presents the first description of its ecology from tracking and camera trapping. We captured five adult lizards weighing 1.0-5.1 kg with snout-vent lengths (SVL) from 40-66 cm and total lengths from 100-164 cm. Activity areas were non-overlapping with a mean of 12,400 m(2); males (23,300 m(2)) had larger activity areas than females (5,200 m(2)). Capture and camera trap records indicate that lizards move most frequently between 1000 and 1500. Movements were characterized by straight line distances between trees with a mean distance travelled between trees of 79 m. Mean daily distance covered was 176 m with larger distances covered by males (228 m vs 142 m for females). Show less
