Full-time indoor cats can escape their home. This means that micro-chipping full-time indoor cats is important. Perhaps it is even more important for full-time indoor cats because if and when they escaped the home they are more likely to be anxious, confused and lost.
Note: disclaimer: I am not a vet but a good researcher. Any doubts about health issues, please see a good veterinarian. Thanks.
Escaping indoor cats
It’s surprisingly common for full-time indoor cats to escape with studies and surveys suggesting that 10-15% of indoor cats escape or become lost at some point in their lives. The figure might be even higher depending on individual circumstances such as access to open doors or windows and of course the carefulness of the cat caregiver.
Whether a cat escapes the home or not also depends on the cat’s character. The more timid, long-term indoor cat might be very reluctant to go through an open door to the outside and a more confident cat might bolt through it. Some cats are more predisposed to the full-time indoor life than others.
Cats are naturally curious and may attempt to dash outside if they see something interesting or if they are startled by a noise or commotion. And cats are very quick and difficult to see sometimes which means they can slip through a door which has been left open by a guest or a visitor. There have been some high-profile escaping cat cases over the years such as the death of the world’s tallest domestic cat, a F1 Savannah cat aptly named ‘Trouble’ [link to that story].
And sometimes changes to the household such as new family members or visitors can cause stress in cats which might motivate them to try and escape the environment to the outside. And of course moving home always opens the door (excuse the pun) to the possibility of a cat escaping.
Also, during warmer weather doors and windows might be left open and cats may be tempted to explore the outside world.
The point is that there is a reasonable risk of an indoor cat escaping and the risk of them being lost or confused after escaping is higher for these cats than for indoor/outdoor cats.
Because of this risk, micro-chipping is as valuable for full-time indoor cats as it is for indoor/outdoor cats.
We all know that micro-chipping is one of the most effective ways to ensure that escaped indoor cat can be identified and returned to their owner. Other forms of identification might be an ID collar or even a tattoo in the ear. They are sometimes used.
In one survey, 15% of cat owners reported that their cats had gone missing at least once in their lifetime. And in an ASPCA study it was found that 74% of loss cats were found but only 5% of those who ended up in shelters were reunited with their owners. This supports the importance of micro-chipping to recover a lost cat.
So there are risks to an indoor cat being lost outside when they escape. So what are the risks of micro-chipping a cat. Are there any risks?
Microchipping risks?
Micro-chipping cats is generally considered to be safe and it is, as you probably know, widely recommended for pet identification. There are some potential risks but they are typically minor.
There might be short-term pain at the site where the microchip is inserted. There might be local irritation, swelling or tenderness at the insertion site for a few days. This normally resolves quickly.
There is a low risk of infection at the site but this is minimised by following proper procedures.
There is a possibility that the microchip might migrate from the site of insertion which is typically between the shoulder blades. This doesn’t pose a risk but scanning might be more difficult.
There is a slight risk of foreign body rejection but this is very rare. In this instance the body treats the microchip as a foreign object. The result can be the formation of a small lump at the insertion site. It normally resolves itself but it may occasionally require removal.
Also, extremely rarely, there might be an allergic reaction. This may be due to the biocompatible materials used in microchips.
Also, rarely, there is the risk of sarcoma formation. This is described as extremely rare actually. Although there have been a few cases reported in veterinary literature. It has not been conclusively linked to the microchip itself in most cases.
Finally, there is a risk of human error when inserting the microchip which might cause discomfort, pain and distress et cetera.
Sarcoma?
On the issue of sarcomas developing at microchip sites they are so uncommon that they are regarded as ‘isolated incidents’ rather than a general risk.
The risk of problems in respect of sarcoma’s is likely to be so small as to be in the region of a few case per million micro-chipped animals. In one report it was said that injection site sarcomas are estimated to occur in one to 10 cats per 10,000 injections which applies to certain vaccines. Microchip-related sarcoma formation is far less common than sarcomas caused by vaccinations.
Risks and rewards?
Above, I discuss the risks of micro-chipping cats and the risks of an indoor cat escaping and the health risks once they have escaped. We have to balance the risks and rewards.
There is no doubt in my mind that there is a strong argument to microchip an indoor cat. The rewards are high because of the possibility of a indoor cat escaping and becoming lost. It’s much easier to reunite a lost microchip cat and one who has not been micro-chipped.
Legal matters UK
A final point. In the UK the law requiring compulsory micro-chipping for cats was introduced as part of the Action Plan for Animal Welfare. It came into effect in June 2024 and under this law cats over 20 weeks old must be micro-chipped and owners who fail to comply can face fines of up to £500. So micro-chipping of cat is obligatory in the UK.
The question of enforcement of this legal obligation is of course another matter. I suspect that some owners of full-time indoor cats don’t think it’s necessary and they may tell themselves that he was going to find out if I don’t microchip my cat? A fair question because it is virtually impossible to enforce this law provided the cats are kept indoors all the time and never escape. But that doesn’t remove the obligation both in terms of the law and in terms of, I would argue, a moral obligation to protect one’s cat is best as one can. Providing security and safety is the uppermost priority of a cat caregiver.
While the primary piece of legislation involved is the Kept Animals Bill, the specific provisions for cat microchipping are implemented as secondary legislation under the broader framework of the Animal Welfare Act 2006.
Sources: various including ChatGPT websearch.
