Mean encounter rate of potential prey species.

<p>Mean encounter rate of potential prey species.</p

Specialization of hunting in the Budongo chimpanzees, 1999–2017.

<p>Specialization of hunting in the Budongo chimpanzees, 1999–2017.</p

Variation in month-to-month hunting of colobus and non-colobus prey by the Sonso chimpanzees.

<p>Monthly rates in panel A and B were calculated by calculating the hunting rate per month for each year, and then averaging across these to control for year-to-year variation within the data sets. Panel A shows the hunting behaviour in the 9-year period from 1999–2007 inclusive; Panel B shows the hunting behaviour in the 9-year period from 2008–2016 inclusive. Panel C and D show the colobus and non-colobus hunting behaviour respectively in the 9-year period from 2008–2016 for each individual year (note that here the axis represents total hunts per month across the 9 years, rather than mean hunts per month, to allow year to year comparison).</p

Means and (ranges) (solid samples in mg/kg, water samples in ppm) for groups of samples.

<p>Key: <i>Na</i> = sodium, <i>K</i> = potassium, <i>P</i> = phosphorus, <i>Ca</i> = calcium, <i>Fe</i> = iron, <i>Mn</i> = manganese, <i>Al</i> = aluminium, <i>Cu = copper</i>, <i>Mg</i> = magnesium. Asterisks indicate that data were not obtained.</p><p>Means and (ranges) (solid samples in mg/kg, water samples in ppm) for groups of samples.</p

Subadult male chimpanzee Frank approaching clay hole (Photo: A. Schel).

<p>Subadult male chimpanzee Frank approaching clay hole (Photo: A. Schel).</p

Results of laboratory analysis (mg/kg for solid samples or ppm for water samples).

<p>Key: <i>Na</i> = sodium, <i>K</i> = potassium, <i>P</i> = phosphorus, <i>Ca</i> = calcium, <i>Fe</i> = iron, <i>Mn</i> = manganese, <i>Al</i> = aluminium, <i>Cu = copper</i>, <i>Mg</i> = magnesium, <i>Cl = chloride</i></p><p>Asterisks indicate that data were not obtained.</p><p>Results of laboratory analysis (mg/kg for solid samples or ppm for water samples).</p

Adult female Nambi (L) using a leaf-sponge at waterhole, watched by 10-yr old juvenile Karo (R) (Photo: C. Hobaiter).

<p>Adult female Nambi (L) using a leaf-sponge at waterhole, watched by 10-yr old juvenile Karo (R) (Photo: C. Hobaiter).</p

Frequency of <i>Raphia farinifera</i> (RF), <i>Cleistopholis patens</i> (CP) and clay, 1991–2014 (Qualitative data).

<p>Frequency of <i>Raphia farinifera</i> (RF), <i>Cleistopholis patens</i> (CP) and clay, 1991–2014 (Qualitative data).</p