Debunking the Dairy Myth

Saturday, 31 December 2005
by Julia_crab of

Don’t feed your crabs dairy! It will kill them!”

I’ve heard this since the first day I found my first crab site on the internet. Everyone says it; it’s “common knowledge.” It is also incorrect.

Like many tidbits of crabbing wisdom, “don’t feed your crabs dairy” is based on conjecture, misunderstanding of nutrition and the properties of food, and is widespread because it’s repeated constantly. However, just because something is repeated over and over again does not make it true; it just makes it familiar.

The reasoning behind the idea that crabs cannot eat dairy is based on flawed information. It is believed, and argued, that crabs don’t have the necessary enzymes to digest lactose, the sugar in milk. Since they are not mammals, they are not equipped to digest lactose. This seems reasonable and logical on the surface, at first glance, and by people with no deeper knowledge of nutrition and the properties of food.

I have been thinking about this problem for over a year, doing research and conducting feeding trials along with several members of my food group, Epicurean Hermit. One of the things that didn’t make sense to me was, if arthropods cannot digest lactose, why is it that there is a creature known as a cheese mite, that lives on cheese?

“Cheese mites can also live in corn, flour, etc., but they are best known for their occurrence in cheese, in which they gnaw small holes. These cosmopolitan mites are common in stored food, damp flour, old honeycombs, and insect collections. A ripe, mite-infested cheese will be more or less covered with a grey powder, which consists of the mites themselves and their moulted skin and faeces. Cheese mites can live at low temperatures but not in the refrigerator. For many cheeses the presence of mites is highly undesirable, but there are some cheeses in which a culture of cheese mites is introduced for example to Altenburger cheese to impart a characteristic “piquant” taste. When the cheese is covered with a greyish powder, consisting of enormous numbers of living and dead mites, cast skins, and faeces, it is considered by some people to be “ripe” and particularly delectable. Cheese can be protected by a thin layer of paraffin wax.

The cheese mite, known to cause dermatitis, is larger than both the grain mite and the mould mite. It has stout, well-tanned, faintly-wrinkled legs (obviously been on holiday) and tanned mouthparts. Males and females are similar except that females are larger. The life cycle requires 15 to 18 days at the ideal temperature of 73̊F and an Relative Humidity of 87%. Unlike the grain mite the hypopus stage does not occur in the cheese mite.”

Furthermore, casein, the protein found in milk, is used extensively in crustacean aquaculture diets; that is, the commercially-prepared feed produced for crustaceans being farmed for food. In aquaculture, it is important to give maxiumum nutrition to cause animals to grow quickly and be healthy enough and attractive enough to make it to our dinner tables. According to Gary Burtle, of the University of Georgia College of Agricultural and Environmental Sciences, in one particular species of shrimp Penaeus vannamei, casein is 99.1% digestible. Many people that are allergic to dairy products are not allergic to the lactose, but the casein found in the foods in question. Casein is used widely in many different diets for many different types of crustacean and is highly digestible across the board.

After doing extensive research along these lines, and questioning scientists when I could, I came to the conclusion that it would be safe to conduct feeding trials of dairy items in my own tank. The hardest part for me, was overcoming the doubts raised in my mind by constantly hearing that dairy was lethal. I had to make a leap of faith. I have great faith in the crabs’ ability to detect whether a natural item is edible by them or not. Their olfactory equipment is as sharp and efficient as that of carrion flies, and they know what compounds to avoid in a natural item. Unnatural and synthetic compounds can confuse their sensory equipment, but if it is a natural, unprocessed food, I firmly believe that they have the ability to detect whether it is poisonous or harmful to them, and whether or not they can derive any nutritional benefit from it.

About February 2005, I started with low-lactose cheese, organic sharp cheddar. It was a massive hit. I noted several crabs, especially cavipes and rugosus, enjoying the cheese I had put in their food dish.

After that trial, I attempted live-culture yogurt, as the bacteria included in the live-culture yogurts digest the little lactose remaining in the food for the eater, rather than depending on the consumer’s own enzymes to break it down for them. The yogurt, also, was extremely popular.

For several months, I communicated with other crabbers who were open to the idea of doing feeding trials and shared my results, while still feeding the occasional treat of cheese or yogurt. Other people reproduced my results, with the same end: i.e., no deaths whether immediate or delayed, no bad molts, and no unusual behavior.

A member of my food group (kuplakrabs) let it be known a few months after I’d announced my results that she had been giving her crabs whole milk for several months. She had had absolutely no unexplained deaths, with the exception of one brevimanus that never ate and died of PPS. I decided to attempt a whole milk trial myself.

The milk was massively popular, with a line of crabs waiting for their turn to have a drink outside the dish. I still have had no deaths in the crabs that I observed drinking the whole milk.

It has been nearly a year since I began feeding trials of dairy products, and I am confident enough in my results to state that dairy is NOT lethal to crabs. They enjoy it immensely.

I am going to continue to feed mine dairy on a weekly to bi-monthly schedule to check long-term effects, but it is not immediately lethal, nor even deadly in the short term.

For the time being, dairy is an acceptable food item, if used as an occasional treat. It should not be relied upon as a regular staple until more research and trials have been conducted, but giving your crabs cheese or live culture yogurt, even a small dish of milk, once every 30 to 60 days is harmless. Be sure, however, to use only organically-produced dairy products, as feed-lot dairy milk is contaminated with antibiotics and growth hormones and these items should be avoided in coenobita diet at any cost.

The dairy myth is dead. Long live cheese.

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