Commonly illustrated in a cartoonish way as Mickey Mouse, Topo Gigio, Speedy Gonzalez, Chip n Dale, and Scrat – among many others, in real life these little toothy animals are the cause of considerable and costly damage to telecom operators and their customers.
To put it in perspective, in 2015 Joe Pinker of The Atlantic magazine wrote an article about how squirrels had been responsible for bringing down the NASDAQ and NYSE on several occasions, resulting in massive losses.
In 2011, Level 3 – now part of Lumen Technologies – confirmed that in that year, 17% of the damage to its fiber optic network had been caused by rodents.
Today it is estimated that 6% of Internet failures in Latin America can be caused by these creatures.
Rafael Goes Barreto, Head of Product and Application Engineering for Furukawa Electric in Mexico, told us that in some countries like Brazil, the problem is so common that the local regulator ANATEL has issued a standard specifically for fiber optic cables with rodent protection.
On the other hand, Ricardo López Corella, from ICE’s Department of Operational Engineering Management, confirms that in Costa Rica the squirrels are so aggressive that they have had to change the same cable segment up to 3 times in 15 days; or, they installed a cable one day and the next day when they went to splice it, the squirrels had already destroyed it –leaving the fibers useless; while on other occasions, they have found damage in up to 8 points in a stretch of just 80 meters (262 feet).
“It seems as if the squirrels enter into a competition to see how many times, they can damage the cable; or how fast after installing it, they can make it useless” said Lopez Corella.
There are several protection options on the market, among the most common are:
- Metallic Armor – these cable designs include a layer of corrugated steel tape, with one or two jackets of polyethylene, which can be very efficient for underground cables, but too heavy for overhead runs (and at least in Costa Rica and Panama, squirrels will break the outer polyethylene jacket and gnaw or tear with their claws on the corrugated steel layer, causing damage to the cables).
- Dielectric Armor with fiberglass. A solution designed for installations that require a dielectric and light assembly. This solution can be efficient in protecting the cables from common mice (Rattus Rattus), although it is not useful in protecting them from squirrels; since, in addition to their teeth, their claws are also long and sharp, allowing them to penetrate to the core of the cable where the optical fibers are located.
- Chemical Additives that are added to the cable’s polyethylene outer jacket. Several companies have invested resources in developing additives based on various chemical substances that could be unpleasant in taste, smell, or sensation for rodents, with aromas that remind them of their predators; or, like capsaicin, a substance derived from chili that many species do not like; however, its efficiency tends to vary greatly depending on the rodent species and the region where it lives.
In Latin America, like many other places around the globe, creativity and ingenuity abound, there are other less common solutions that are often developed by contractors and their teams of engineers and installation technicians. For example:
- PVC pipes – the cable is put into PVC ducts with a diameter greater than the rodent’s jaw reach; Lopez Corella confirmed that in Costa Rica some operators tried this method; but besides being expensive and not very aesthetic, it did not work.
- Mechanical Grease – the cables are smeared with these compounds, which can work as long as they are not removed by rain or other elements, so it is not viable as a long-term solution either.
- Reduce Polyethylene Odor Intensity – One of Barreto’s customers allowed cables to be in storage for 1 to 2 years before installing them; this allowed to reduce the intensity of polyethylene’s odor on the outer shell – apparently something that attracts squirrels (something not so viable in this fiber-hungry world that requires making use of the fiber optic cables as soon as they reach the customer). It did not prove to be reliable.
Understanding the problem
Barreto affirms that, to understand the problem, we must see it from the rodent’s point of view. “Their main motivator is survival, since their front teeth (incisors) never stop growing, so gnawing is a matter of survival; If they did not, it would not be possible for them to eat and they would starve to death”, said Barreto.
Additionally, squirrels are very territorial, so when an object, that is not naturally found in their habitat, nor has it been present since birth, shows up in their environment, they run to inspect and attack such intruder.
It is also important to know the length of their incisors and claws, as this allows us to understand how deep the outer protection must be so they cannot damage the fibers.
The industry has continued to innovate, some of the latest designs include:
- Flat FRP Armored Cables – a layer of thin sheets made with the same material as the cable´s central strength member: Fiber Reinforced Plastic (FRP). This method has been very efficient in protecting cables from mice, but not from squirrels.
- FRP Rod Armored Cables –in this case the rods are made from the same FRP material, but they are thicker, making it more difficult for the claws or teeth of the squirrels to reach the core of the cable, a solution that both Barreto and Lopez Corella confirm has been highly effective in protecting cables from squirrels.
These last two options seem to be gaining momentum in the market, where several cable manufacturers already offer products with such characteristics and operators are benefiting from them. Some of the companies that offer one, or both options, include: Furukawa Electric, Prysmian, Corning, Incab, ARTIC LATAM, Sterlite, LS Cables, Taihan, ZTT, and FiberHome, among others.
Like everything in life, there is no ideal solution for all situations. Many factors must be considered in deciding which is the best option. For example, what type of a link it is, how aggressive are the rodents in the area, and what is the probability of damage. Depending on the aggressiveness or presence of rodents in such area, some less costly and lighter solutions can be implemented; whereas, for a backbone in a high-risk area, it is extremely important to maintain cable integrity at any cost.
As pharmaceutical companies would say: check with your cable providers to see what the best option is for your situation and tell us about your experience in dealing with those little furry animals.