Physically speaking, the Aeçeux are a humanoid race with physiology resembling a marine mammal's, but visually resembling more of an amphibian. Unlike the Shichirin and the Mbinanto, which are still able to be classically defined, the Aeçeux defy classical definition by being directly comparable to different families of animals, and simultaneously perfectly fitting none. In general, the Aeçeux are similar to humans in height, and would be considered ectomorphic by human standards. However, life underwater is strenuous enough that they tend to be very in shape. Their coloration varies with pigments of yellow and blue to make greenish hues, and while under water the colors are muted and barely recognizable, on land they are very vibrant and obvious. Across their bodies, the Aeçeux have fins that, while somewhat relevant to their movement abilities, are smaller in size and mostly vestigial. They also have webbing between their finger and toes, which are their main source of underwater mobility and agility. Along their inner legs, the Aeçeux produce a substance that is particularly self-adhesive, and while the Aeçeux prefer to have their legs separated, they are much faster and much more energy efficient when they swim in a manner similar to a dolphin. Along their necks, behind the major arteries, they have a set of slits that open to an organ that separates oxygen out of water, allowing them to breathe with their lungs. Their bodies produce a sort of mucus naturally using moisture around them, and while it is normal for them to be mostly dry on land, a complete stop to production is a sign of faltering health. Out of water, their bodies dry and tend to change because of it; their fins shrink and stiffen particularly on their head and face regions, and their webbing recedes just beyond normal for a human being. The Aeçeux are sexually dimorphic, but their cultures tend to be fairly equal in spite of this; males tend to be more physically able than women, but the gap between them in most situations isn't incredibly large due to the level of fitness their environment requires. That said, their perceptions are not entirely equal, and can lead to problems in particular with the Mbinanto and the Shichirin, which have women of equal and greater physical fitness respectively. A main physical difference between the sexes is that the vestigial facial fins of the males are larger, and their hair grows more slowly, while the facial fins of females are smaller, and their hair grows much more quickly; each of these respective attributes is generally seen as attractive to the opposite sex. Females tend to keep their hair long and in very intricate hairstyles that keep the drag out while swimming, while men tend to keep their hair short to display their fins; when males let their hair grow, and when females keep theirs short, it is seen as a sign of unavailability or disinterest, or potentially in the case of a female a sign of a more masculine occupation. On top of their facial characteristics, coloration between the two genders varies, with males taking on a much more vibrant coloration than the females.