Giant Squid

Distribution: As previously mentioned, Architeuthis are dispersed all over the world. Records of their locations include the African waters of the South Atlantic Ocean, and the southern Pacific Ocean near Australia and New Zealand (TOLWEB, 2015). Architeuthis have also been found in areas of the North Atlantic Ocean, such as Newfoundland, the British Isles and other oceanic islands (TOLWEB, 2015). Lastly, areas of the North Pacific around Japan have produced evidence of Architeuthis (TOLWEB, 2015). Through giant squids have a wide range of habitats, finding samples of this elusive invertebrate in tropical waters is rare (TOLWEB, 2015). Evidence of the giant squid's presence is also seldom found in Polar Regions (TOLWEB, 2015).

ocean.si.edu

Interesting Features: Giant squids are very large, but other than their massive body size, Architeuthis have another, large, interesting feature: their eyes. In Nilsson et al’s article “A Unique Advantage for Giant Eyes in Giant Squid” the scientists wanted to study what adaptive pressures the giant squid faced resulting in the invertebrate’s massive eyes. To answer this question, the researchers developed mathematical formulas to calculate the size of the squid’s eyes in relation to their ability to see different objects, and in varying light conditions.

The eyes of the giant squid are about the size of a soccer ball, making them, potentially, the largest eyes in the animal kingdom (Nilsson, 2012). The number of measurements for the Architeuthis’ eyes is few but researchers suggest that their eyes may range between 250 mm to 400 mm in diameter (Nilsson, 2012).With their large size and large eyes accounted for scientists have become curious as to why the giant squid requires such over sized features. The idea that Architeuthis use their size and eyes to avoid predators has been suggested for many years. Giant squids are so large that there are not many deep-sea creatures that can prey on them (Nilsson, 2012). However, the remains of giant squids have been found within sperm whales, implying that the massive mammals prey on the also massive giant squids (Nilsson, 2012). Sperm whales use sonar to search for their prey but giant squids are not able to hear the high frequency of the whales sonar so, because Architeuthis cannot hear their predators approaching, they must rely on their large eyes in order to escape doom (Nilsson, 2012). Architeuthis likely have a visual range of 120 meters, but this enormous range does not provide the squid with enough time and space to avoid their predator completely (Nilsson, 2012).

The energy needed to support such a massive pair of eyes is parallel to the size required to house such large eyes (Nilsson, 2012). It is not hard to believe that these traits also provide giant squids with the strength and ability to escape (Nilsson, 2012). Sperm whales, however, still catch their giant prey, implying that the evolution of Architeuthis’ large size and eyes may be driven by their desire to avoid their main predator, the sperm whale (Nilsson, 2012).

If giant squids have evolved to escape from sperm whales then it is not hard to believe that these same abilities have allowed Architeuthis to elude human beings for many years (Deagle, 2005). This suggestion does bring attention to the matter of how Architeuthis catch their own prey. Do they use these same skills to catch fish, other cephalopods, and even other giant squids?

The focus of Seibel et al’s study “Light-limitation on Predator-prey Interactions: Consequences for Metabolism and Locomotion of Deep-sea Cephalopods” was to identify a correlation between metabolism and locomotor performance, but their results shed light on the possible hunting methods of giant squids as well. Seibel et al focused their research on twenty-five different species of cephalopods surrounding California and Hawaii (Seibel, 2000). The researchers’ single sample of Architeuthis was collected by a charter-boat in 1999 (Seibel, 2000). The sample was brought to the scientists dead, and chilled for three days before dissection (Seibel, 2000).

Following their examination, Seibel et al’s study concluded that giant squids are a sit-and-wait predator (Seibel, 2000). Architeuthis collect ammonium in their muscles for buoyancy, leading to the suggested sit-and-wait method (Seibel, 2000). This may seem conflicting to the idea that giant squids have evolved the ability to avoid sperm whales only to sit-and-wait for their own prey, but that is not necessarily true. It is believed that the weak muscle tissue of Architeuthis may limit the squid’s ability to rush into swimming, so giant squids’ cruise when necessary (Seibel, 2000).