An Amazon cruise allows travelers to glimpse a number of unique and beautiful animals during their excursion, but that is a perk not solely reserved for the river proper. The 1,200-mile long Rio Ucayali is one of the many offshoots of the complex river system, and offers a wealth of wildlife both along its shores and in its waters.

Among the more unique species found in the river is the Amazon river dolphin, a wondrous species that is most easily identified by its pinkish hues. While rare in other parts of the Amazon, pink river dolphins flourish in the Peruvian Amazon, and International Expeditions’ Amazon expedition cruise guests see these mysterious mammals almost every day! These creatures play an interesting role in local culture, with many native tribes telling stories of the legendary encantado, a river spirit that can transform from a dolphin into a man to seduce local women.

Scientifically, these creatures are just as interesting. One of only five river dolphin species, the pink dolphins (or Bufeos as they are locally known) are larger than their saltwater counterparts and bear no dorsal fin, instead featuring a large hump in their back. Their pink color is also a mystery to scientists. The bufeos change colors constantly, from grey to pink. No one knows for sure why they have this color and why they change it. Capillaries close to skin surface might be the main reason for this unique coloration and its changes – the more activity the more blood circulates and the pinker the hue. Other factors could be age — juveniles are mainly grey, levels of iron in the water and water temperature.

These endangered creatures are also considered among the smartest creatures in the animal kingdom, possessing a brain that is 40 percent larger than that of a human.

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