(A) Comparison between weights of stones used by macaques on Koram and NomSao Islands to open oysters. The plot shows all quantiles and the CIs (grey). (B) Comparison between weights of stones used … see more
Stone tools used.
Shellfish foraging stone tools collected on Koram and NomSao Islands, Thailand.
(A) Weight of stones (with bootstrapped 95% confidence intervals) found on Koram and NomSao Islands, separated for oyster bed and tidal. (B) Average stone availability per island, separated for … see more
Natural stone availability and weight.
The number and weight of stones located in 20 × 20 cm plots on Koram and NomSao Islands, Thailand.
Snail availability.
The number of snails located in point transects along the shore of Koram and NomSao Islands, Thailand.
(A) Average size of oysters (with bootstrapped 95% confidence intervals) found on Koram and NomSao Islands. (B) Average snail size (volume) (with bootstrapped 95% confidence intervals) found on … see more
Oyster size.
The size of rock oysters measured in width and length on Koram and NomSao Islands, Thailand.
Snail size.
The size (length) of three marine snails (N = 100 each) on Koram and NomSao Islands, Thailand.
(A) Adult male long-tailed macaque using a stone tool to crack open a snail. (B) Size difference between NomSao and Koram Islands of most commonly harvested snails. (C) Abandoned macaque tool at … see more
Koram Island shellfish foraging.
The number of prey items consumed during behavioral observation of daily shellfish foraging on Koram Island, Thailand.
Maturation stages.
The size and maturation stages of the main prey species harvested by tool using macaques on Koram and NomSao Island, Thailand.