However, certain wasp species such as pollen wasps have similar behaviours, and a few species of bee scavenge from carcases to feed their offspring. The world's largest species of bee is thought to be the Indonesian resin bee Megachile pluto, whose females can attain a length of 39 millimetres (1.54 in).
For a Ph.D. in Psychology: Most Ph.D. programs require at least 5 to 7 years to complete. In addition to regular coursework, you may also be expected to complete an internship or supervised residency. The program usually culminates in completing an original research project or dissertation.
As stated above, the PhD can take up to 8 years, with the average time being around 5 years. But it does vary considerably depending on a lot of factors (subject, research, supervisor, funding, problems...). As of 2007, the average length for a PhD was 8.2 years.