Cleaner Shrimp

Cleaner shrimp are a feature of the sea. When people envision a coral reef, cleaner shrimps are one of the primary features they think of outside the corals and the fish. Cleaner shrimp even appear in popular culture, with one featuring in one of the Finding Nemo movies.  However, they remain largely unstudied in light of origins, and even in the general scientific community.  This article will examine cleaner shrimp in light of some recent research and explain why they could not have developed by chance.

For those that may be unaware, cleaner shrimp are specialized shrimp that exist by cleaning small fish. The fish are willing partners in this endeavor. The shrimp set up stations around the reef and the fish pull in as a car would pull into a car wash.  The fish do not eat the shrimp. Instead, they open their mouths and their gills and allow the shrimp to crawl over them and into their open mouths and gill flaps. The shrimp remove parasites from the skin, mouth, and gills of the fish, enabling it to be healthier. They also remove dead tissue and even some scar tissue, permitting the fish to heal more easily. While this is beneficial to the fish, it is also beneficial to the shrimp. The shrimp eat the tissue and parasites they remove. Thus the shrimp gets a free meal, while the fish effectively gets a free doctors’ visit. Both parties benefit from this mutualistic relationship.

One of the big questions about cleaner shrimp has always been, “Why don’t the fish just eat them?” and this is a very fair question.  A recent study out of Duke University has helped shed some light on the subject. Researchers studied the interactions of one species of cleaner shrimp, Ancylomenes pedersoni commonly known as Pederson’s cleaner shrimp, with numerous species of Caribean reef fish. The results were quite illuminating. The researchers observed almost two hundred visits to the shrimp’s cleaning stations and observed some patterns.  When the fish arrived at the station, they would hold very still, a tactic referred to as posing. This tactic effectively served to ask the shrimp if they were open for business. The shrimp would then decide if they wanted to clean the fish and, if they did, they would wave their antenna, indicating they were available to clean. In response, the fish would rapidly darken their pigmentation, telling the shrimp they did want to be cleaned.  Since the shrimp are color blind, this change of light to dark makes an excellent signal. This worked in eighty percent of cases, which is a fairly high rate of success.  While this study was illuminating as to how the process worked, it left unanswered the question of why the shrimp do not get eaten.  While the article in National Geographic‘s website, which I’ve linked to below, does comment on this issue, it fails to provide answers.

Cleaner shrimp are not the only animals that use cleaning as part of their lifestyle. Some fish and even a few birds do so as well.   Shrimp and fish are the ones which present the biggest challenge to evolutionary theory.  How do fish know that the shrimp are willing to clean them? And why do the fish not simply eat the shrimp? How do they know it is more beneficial to pass up a free meal and get cleaned than to eat the free meal and not get cleaned? These are major problems for evolution, for which they have yet to find a solution.   Because evolution is a blind, unguided, purely naturalistic process, it cannot be looking towards the future. It can only be concerned with the immediate present and thus can only produce creatures that are blind to the long term. Allowing a shrimp to clean it is the fish thinking about its long-term health, rather than its short-term hunger.

Even supposing that the fish had somehow evolved the ability to refrain from eating the cleaner shrimp, evolution still has massive problems with cleaning behaviors. The cleaner shrimp and the fish it cleans must both have evolved their behaviors simultaneously. Any other method results in dead cleaner shrimp, either from starvation or from becoming the fishes lunch.  Since dead shrimp don’t breed and pass on their genes, this would have stopped evolution right there.  However, even making this second assumption that the two evolved simultaneously in the same place, there are still issues. Where did the behaviors that regulate this cleaning come from? How do shrimp know that the fishes color change signals they want to be cleaned? How does it know to wave its antenna as a signal to the fish that it will clean it? How does the fish know which shrimp are cleaners? How does it know that the waving antenna means the shrimp will clean it? How does it know to change colors to tell the shrimp it wants to be cleaned? I challenge evolutionists to produce answers to these questions.

Creationists have no problem with cleaner shrimp or any other kind of cleaning animal. They reflect the design of an all-wise Designer Who built into His creation these remarkable, specialized abilities that cause predator and prey to work together for mutual benefit.  This specialized design is the answer to all the questions evolutionists can’t answer.


National Geographic Article

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