There is now a wealth of evidence on how, when and where HIV first began to cause illness in humans. You can find out more about the origins and history of HIV through our interactive timeline , where you can read, watch, listen and explore key events from the history of the epidemic. The researchers who discovered this connection concluded that it proved chimpanzees were the source of HIV-1, and that the virus had at some point crossed species from chimps to humans. They discovered that the chimps had hunted and eaten two smaller species of monkeys red-capped mangabeys and greater spot-nosed monkeys. These smaller monkeys infected the chimps with two different strains of SIV.
Do animals have sex for pleasure?
BBC - Future - Do animals have sex for pleasure?
Transient global amnesia is a sudden, temporary loss of memory that's not attributable to any common neurological condition. So what can cause it? Along with a very short list of other causes that also includes sudden immersion in hot or cold water, sex can literally wipe your memory. Thankfully, the condition is rare, temporary, and not likely to recur. But why does this happen?
Is oral sex natural, and do only people do it?
That's because most scientific accounts of sexual behaviour rest upon evolutionary explanations rather than the more immediately relevant mental and emotional experiences. To say that we have sex because it helps us to preserve our genetic legacies would be entirely accurate, but the more fleeting, experiential, pleasurable aspects of that most basic of social urges would be missing. It would be like staring at a painting with half the colour spectrum removed from it. One thing we have been curious about, though, is whether we are the only species that experiences sexual pleasure. The question of whether non-human animals enjoy it too is a perennial — and scientifically legitimate — question to ask.
Visit our Re-post guidelines Viagra is a multi-billion dollar blockbuster drug, but it has serious side effects. Thankfully evidence-based natural alternatives abound Erectile dysfunction is no trivial matter. Mercola correctly labeled it ' the canary in the trousers ,' insofar as dysfunction 'where it counts' reflects body-wide endothelial dysfunction , a well known precursor to cardiovascular disease.