Froggy Pond Redux: Clever Cuttles!
The cache, a small flip-topped tablet pot, is hidden on the extensive granite slabs overlooking, to the south, the locally popular Froggy Pond – a small bay with a fine sandy beach and nearby granite rock formations, above and below the water.
It is a replacement for GC6YJBK Froggy Pond (What's in a Name?) which was hidden on 27/12/16 and archived on 15/12/22 after some 80 finds and 1 FP. See the old cache description for detailed info on Froggy Pond as a dive site, including details of the features and creatures to be seen.
It is a sheltered, shore-entry rocky dive site with lots of red, green and brown seaweed. Although there are not a lot of fish, cuttlefish (see below) and octopus are always present. It is ideal for relaxing dives and for setting up diving gear for exploring other dive sites in the area, such as the adjacent A-Frame to the south.
To Reach the Cache Location: park on the verge of Cruywagen Rd near S 34 12.142 E 18 27.283, cross carefully over the M4 road then head down to the small beach access gate near S 34 12.184 E 18 27.373. Follow the trail down and around to the granite slabs, then head the short distance across to the cache location.
Cuttlefish or cuttles (aka ink-fish) are marine molluscs in the same family as squid, octopus, and nautilus. They have a unique gas-filled internal shell, the cuttlebone, which is used for buoyancy control. At least 6 species are regularly found in SA waters. The most abundant and largest species - and that most frequently seen by divers - is the endemic Common* or patchwork cuttlefish (Sepia vermiculata) which is found around the southern Africa coast from Mozambique on the east to the Orange River mount on the west. It grows to 49cm mantle length and up to 4kg weight. *Common cuttlefish is most often used for Sepia officinalis.
It has an elongated body with 10 arms bearing rows of suckers. Two arms are elongated tentacles used for catching prey. Paired lateral fins extend the whole length of the body like a skirt. The upper surface of the body is smooth, with rippling bars of colour and the animal is usually well camouflaged.
It lives in sheltered lagoons, estuaries and the open ocean to depths of 200m feeding on shrimp and small fishes. Its eggs are pea-like, black or white and are usually attached to sea fans.
Known as the ‘chameleon of the sea’, it is capable of rapid changes of colour for camouflage, threat displays or for communicating mating readiness. A male ready to mate will show dark brightly rippling colours as he approaches another cuttlefish. If the other cuttlefish is either a male cuttlefish or a non-receptive female, the other cuttlefish will also show dark brightly rippling colours as a threat display. If the other cuttlefish is a receptive female, her colours will remain pale and head-to-head mating will take place. It may also lift two arms above its head when disturbed, possibly as threat gesture.
These colour changes are produced by special cells (chromatophores) located in the outer-skin layers, 
.which contain colour pigments, typically red, yellow, brown, black and blue. They can be expanded to display a large area of colour, or contracted to a tiny speck – all done by neural control (ie. merely by thinking about it!).
It is the only southern African species of cuttlefish to enter lagoons and estuaries having been recorded in Langebaan Lagoon and Knysna Lagoon as well as the mouth of the Kowie River.
They eat small molluscs, crabs, shrimp, fish, octopus, worms . . . and other cuttlefish! Predators include dolphins, sharks, fish, seals, seabirds . . . and other cuttlefish. Typical life expectancy is about 1–2 years. They are among the most intelligent invertebrates having one of the largest brain-to-body size ratios, and have amazing hunting and evasion abilities. See here for a short video on an interesting intelligence test with cuttlefish.
Some QI cuttle facts . . .
1) They have very sophisticated eyes fundamentally different from vertebrates. Although they can’t see colour, they can perceive the polarization of light, which enhances their perception of contrast. The eyes fully develop before birth, and start observing surroundings while still in the egg. So, they may prefer to hunt the prey they saw before hatching!
2) They have green-blue blood because it uses the copper-containing protein haemocyanin to carry oxygen instead of the red, iron-containing protein haemoglobin found in vertebrates' blood. It is pumped by three separate hearts - two pumping blood to each of the cuttlefish's pair of gills and the third pumping blood around the rest of the body.
3) They have an internal structure called the cuttlebone, which is porous and made of aragonite a form of 
calcium carbonate. Its pores give buoyancy, which the cuttlefish regulates by changing the gas-to-liquid ratio in the cuttlebone chambers. Each species' cuttlebone has a distinct shape, size, and pattern of ridges or texture. It is unique to cuttlefish, and is one of the features distinguishing them from their squid relatives. They are often seen washed up on the beach and can be given to parakeets and other cagebirds as a calcium supplement and to sharpen their beaks.
4) They have ink stores like other marine molluscs used for chemical deterrence, phagomimicry (mimicking food), sensory distraction, and evasion when attacked. Ink is ejected to create a ‘smoke screen' to hide the cuttlefish's escape, or released as a pseudomorph of similar size to itself, acting as a decoy while it swims away.
Uses: As food – they are caught for food in the Mediterranean, East Asia, the English Channel, and elsewhere. Their ink used to be an important dye, called sepia. Metal casting: cuttlebone has been long used to make casts for metal. A model is pushed into the cuttlebone and removed, leaving an impression. Molten gold, silver or pewter can then be poured into the cast.
Smart clothing: research into replicating biological colour-changing has led to engineering artificial chromatophores out of small devices known as dielectric elastomer actuators. Soft materials have been made that mimic the colour-changing skin of animals like cuttlefish, paving the way for ‘smart clothing’ and camouflage applications.
See here for more information on this fascinating creature.
Video links: see here (cuttlefish facts), here (cuttlefish at Glencairn), here (amazing cuttlefish performance), here (BBC Blue Planet 2: cuttlefish hynotises prey) and here (BBC BP2: cuttlefish mimics being female to mate).
