A battle is raging in California between two species: benign, slothful potheads versus driven, Machiavellian yuppies.
It's the willing collaboration between two species, a sharing of benefits.
Müllerian mimicry can occur between two species that are distasteful to the same predators.
One group of neurons could help to explain the difference between two species.
Parallelism and Epistasis in the de novo Evolution of Cooperation between Two Species.
When presented with choices between two species, seals apparently showed consistent preferences for particular species.
Because of these similarities between two species, A. tuncelianum has been locally called "garlic".
Montbretia was a hybrid between two species of this lovely South African genus, a cross aimed at producing a select plant with adequate hardiness.
All kinds of critters, not only humans, frequent fig trees, but the plants owe their existence to what may be evolution's most intimate partnership between two species.
Interbreeding 50,000 years ago between two species of human may also have bequeathed a sunburn hazard called keratosis, addiction to nicotine, and a greater risk of depression.
Soto Àngel believes this is the first time an example of such specific behaviour and such a specific relationship between two species has been discovered.
