Many of the electron micrographs which start as monochrome images have been colorized by Dennis using software such as Adobe Photoshop to produce truly amazing images. Djungarian hamsters, native to Russia, experience a sympathetic pregnancy when their mate is gestating and also act as midwives. They even ensure the newborn offspring can breathe freely by licking them clean of birth membrane and then help the mother to recover. Researchers have found that male hamsters increase production of female hormones such as oestrogen and cortisol in the weeks before their mates give birth, making them more feminine. This hormonal change is thought to give rise to the nurturing behaviour.
Djungarian fathers have hormonal fluctuations similar to the mother's around the time of birth.
Because the hamsters come from the harsh desert regions of Siberia the researchers also believe evolution has helped sharpen the male hamsters' nurturing instinct.