EarthFlip the birds: Migration began in the north not south American songbirds migrate to escape harsh northern winters, rather than to enjoy rich northern summers as many biologists thought ¿ìè¶ÌÊÓÆµ
LifeEvolution of placentas upended fish sexual politics When animals evolved placentas to feed their young, it may have allowed them to be less picky about their sexual partners ¿ìè¶ÌÊÓÆµ