Planet of origin : Hudlar
Hudlars are a sentient species that will be member of the same interstellar Federation at some point in the future. Massive, they ressemble two-ton armadillos. They are oxygen-breathers but can go without air for long periods and can work comfortably in the vacuum of space. They can survive radiation doses that would kill many races. Their skin is flexible but extremely tough and with very few orifices: temporary ones form for mating and giving birth. Hudlarian eyes are deeply recessed and protected and speech is via a bellowslike cock's comb flap on the back of the head, which they also use for hearing. Breathing, eating and excreting happen through different areas of the skin, in some places pitted with thousands of tiny slits.
They have six thick tentacles, which end in hardened pads that form "knuckles" for them to walk on, and manipulative clusters of four, hard-tipped specialised digits which curl inward for protection.
Hudlar's home gravity approaches 4G and the atmosphere is a thick, semi-liquid soup with a pressure of 7 atmospheres. This provides them with all the nourishment they require; offworld they spray themselves with nutrient "paint". Many Hudlars work offworld; the planet is poor, with no mineral resources, fabricated items, or tourist attractions, so the inhabitants sell their labour. They need to eat frequently, but can go for long periods without sleep.
Young Hudlars are prone to a number of spectacular diseases which are only life-threatening when they combine, but adults are virtually immune to disease and very hard to injure. Their immune systems are so efficient that transplants require it to be artificially suppressed, after which the recipients may no longer come into contact with others of their kind or they may die. Problems also arise in old age, when the two hearts can no longer maintain the high metabolic rate. This leads to a number of unpleasant effects including necrosis of the limbs, failure of the food absorption mechanism on their flanks, distortion of the speaking membrane and loss of control of the underside waste elimination area. Aged Hudlars often go insane as their bodies let them down.
Hudlars mate for life, and only share their names with their life-mates and close family. After giving birth the female gradually becomes male and her partner does the opposite. Death is never mentioned, and the bodies of the deceased are ignored. Hudlars are frequently gentle, inoffensive and self-effacing.
Their music sounds like whistling moaning.
Sources: James White, novels of the Sector General Universe
John G. Wood at: http://www.elvwood.org/Gurps/SectorGeneral/Hudlars.html