rding to Lesley J. Rogers, "Only from the animals that have learnt to communicate with us by signing or pointing to symbols can we expect to find out what they are thinking about" (176). The three book resources all agree that there are two types of sleep. The first is a relatively low-frequency pattern or a deep sleep. The second is called REM sleep. This is an irregular sleep and is accompanied by rapid eye movements (REM's). Humans are more likely to say they were dreaming during REM sleep. Comparable recordings from sleeping birds and mammals show similar patterns of REM sleep, indicating that they also dream (Griffin 259). Although Gould agrees that some birds and mammals do have phases of REM sleep, which suggest the animals are dreaming, he also believes body movements effect the dreams. According to Gould, "Until recently, about the best evidence for dreaming in animals came from casual observation of pets, who sometimes in their sleep exhibit body movements (including running, biting, and mating) and produce subdued vocalizations that suggest they are reliving an experience" (168). It is still hard to determine for sure that animals can dream but if there were some way of knowing for sure it would be very interesting. To my knowledge, no one has attempted to ask sign language trained apes about their dreams, but it should be possible (Rogers 177). If it is possible to ask the apes then why doesn't anyone ask? I guess we will never know for sure if the apes are never given the opportunity to answer. The only evidence that we have right now is the REM sleep and body movements. Even with this evidence, are they sure that the animals are really dreaming? According to Griffin, "Darwin and many others have been impressed by the fact that sleeping dogs sometimes move and vocalize in ways that suggest they are dreaming; their movements resemble those of feeding, running, biting and even copulation. They sometimes snarl ...
