Crypsis
H. impatiens is a particularly cryptic species. During the day they can only be spotted if large coral rubble assemblages are turned over. They are a nocturnal species but even at night it is extremely difficult to spot them (Figure 4). By loosening the muscles in its body wall, an individual can essentially liquefy itself and mould its body into a tight crevice. Figure 3 shows a dissection of a Holothurian impatiens, here, the longitudinal muscles are clearly shown.
Figure 3: Muscles in Holothuria impatiens body wall.
Once the sea cucumber is satisfied with its location it then tightens the collagen fibers in its body to become firm. By doing this, the animal is secure and protected. During feeding time at night, h. impatiens will only protrude half of its body, ensuring the reaming half is still weaved within the coral assemblage. This makes the animal extremely difficult to spot. Attempts to pull this animal out of its crevice are mostly unsuccessful.
Figure 4: Images taken during the night. The cryptic Holothuria impatiens |