Breeding pair insect. True breeding pairs are rare in amphibians or reptiles, although the Australian Shingleback is one exception with long-term pair-bonds. Some fish form short term pairs and the French angelfish is thought to pair-bond over a long term. True breeding pairs are quite common in birds. Breeding pair arrangements are rare in mammals, where the prevailing patterns are either that the male and female only meet for copulation (e.g. brown bear) or that dominant males have a harem of females (e.g. walrus). Breeding pair Breeding pair is a pair of animals which cooperate over time to produce offspring with some
What Is and What Should Never Be (Supernatural) What Is and What Should Never Be (Supernatural) "What Is and What Should Never Be" is the twentieth episode of the paranormal drama television series "Supernatural"s second season. It was first broadcast on May 3, 2007 on The CW. The narrative follows series protagonist Dean Winchester (Jensen Ackles) who finds himself in an alternate reality after a confrontation with a djinn . The creature appears to have fulfilled Dean's greatest wish: that his mother had not been killed when he was a child. Dean is happy in the new world until it becomes apparent that his previous work as a