Evolutionary ecologist interested in the causes and consequences of variation in natural populations. In particular, what are the ultimate and proximate drivers of variation between individuals in immune responses, infections, life-history and senescence rates. I study longitudinally-monitored populations of wild(ish) sheep, elephants and people. Most of my work uses long-term data collected from these populations, but I'm becoming more interested in measuring the physiology associated with life-history variation and the link between reproduction and immunity in particular.