Average nitrogen isotope ratios vary across the food chain
The nitrogen isotope ratio δ¹⁵N of air is set to 0 permil (‰) and used as a standard to compare mean values from animals and plants. Higher values of this ratio mean higher levels of nitrogen-15, which increases higher in the food chain. Maggots feeding on decomposing meat have the highest δ¹⁵N values.
A bar graph showing the average nitrogen isotope ratio from grasses, air and various animal sources including Neanderthals, rotting meat and maggots. Grasses have the lowest value of -0.1%, the value for air is 0, deer, a herbivore, has a value of 0.48%, Neanderthals are at 1.11% and maggots at 2.4%
