PROOF OF IDENTITY
When does someone become something?
A number written in marker. A band fitted around a leg. A tag attached to an ear. A mark made directly onto the skin.
All of these markings can distinguish one animal from another. Some are temporary, while others remain with an animal for their entire life. The methods and materials vary, but all these practices organize breeding and mark ownership.
I’ve long been interested in the moment an individual is tagged and becomes part of a larger system of organization. Rather than being recognized by their unique markings, personality, or voice, the animal’s identity becomes reduced to a number.
Through the We Animals Fellowship, I investigated agricultural tagging practices in the northeast United States, observing and photographing some of the most commonly used methods.
In agricultural settings, an outsider’s interest in the animals themselves, rather than their economic value, will raise suspicion. Because access to industrial farms is extremely limited, I focused on smaller farms that were willing to open their doors, although these identification practices are carried out on a much larger scale in industrial farming. Through these photographs, I invite you to look closely at the objects used to identify animals and consider how a living body becomes a surface for information.
Tagging
Ear tags are among the most familiar forms of animal identification, particularly for cattle, sheep, and goats. The tags come in a variety of colours and sizes and are attached directly to the animal’s ear, usually in both ears for easier visibility. In the United States, the USDA will provide official identification tags to eligible livestock farms at no cost through state animal health offices. These tags are used to identify animals and trace their movements, helping authorities monitor and respond to disease outbreaks. These tags are illegal to remove.
Each farm has its own approach to animal identification. At an Angus farm I visited, calves were given an ear tag at birth to establish their identity from the beginning. These tags were hand-engraved by the herd manager. The calf’s identification number was engraved in the centre, with its sire’s and dam’s numbers also on the tag, linking the calf to its parents.
At nine to ten months, when I visited, the cattle received a matching tag in the opposite ear for ease of identification in a large field and in case one tag fell off. The third tag attached was used for official identification under the USDA’s animal disease traceability system. The cows were also given a tattoo with identification numbers on both ears. To improve efficiency, the farm had a head scoop, a specialized attachment on the cattle handling crush that restrains the cow's head. The cattle were not given pain medication before or after the procedures.
Ear tags will sometimes tear out of an ear, leaving a hole or scar. When another tag is needed, it's often applied with a new puncture; this is why you sometimes see an animal with a hole in their ear. To pierce the ear, companies producing these tags provide a handheld applicator with a pointed pin to pierce the ear and fasten the two parts of the tag. When applying the tag, farmers aim between the larger veins of the ear to reduce bleeding. Cleaning and disinfecting the applicator between animals is recommended but not always followed.
Leg Banding
Leg bands are used to identify birds, distinguishing individuals within a group. They may carry numbers or colours and are commonly made from aluminium, brass, or plastic. The purpose of this tag depends on the context in which they are used.
Chickens are the most slaughtered land animals, and in industrial poultry production, individual leg bands are generally impractical. On large operations birds are tracked via their flock.
To witness the process for leg banding i spent time with a poultry tester in Maryland. I followed her to private residences to document poultry disease testing ahead of the local county fair. Chickens received oral swabs for avian influenza and blood samples for Pullorum-Typhoid testing with an accompanying state-issued aluminum leg band. The visits included backyard flocks and young 4-H exhibitors preparing their birds for competition.
Tattooing
Tattoos are a popular method of tagging animals, specifically pigs, cattle, and rabbits. This method places a permanent number on their body, usually within the skin of the ear. Depending on the purpose and species, tattoos may use numbers, letters, or other codes to distinguish individuals.
These photographs document the tattooing process used in a commercial Angus beef operation in Maryland. Cattle are moved individually through a narrow chute into a steel restraint system. After receiving an electronic identification (RFID) tag and two numbered ear tags, each cow is tattooed in both ears using a tattoo punch. The fresh wound is rubbed in with green tattoo ink to make the identification marks visible.
In rabbits, tattoos are commonly used in breeding and exhibition settings because, like an ear tag, a tattoo cannot snag on cage wire. And although less common today, tattooing the inside of the upper lip was once standard practice for identifying Thoroughbred racehorses.
Tattooing is widely used in laboratory research to identify rats, rabbits, and dogs, allowing researchers to distinguish individual animals and link them to experiments. Depending on the species and facility, tattoos can be applied to the ears, tail, or feet.
"What stayed with me was the ordinary nature of these gestures—a number engraved into a tag, ink rubbed into a fresh wound, a notch of skin removed from an ear or a scribble written directly onto the body."
Branding
Branding has long been used to identify animals in agriculture by marking ownership directly onto their bodies. Hot branding uses heated irons to burn marks into the skin, while freeze branding uses extreme cold to alter hair pigmentation. Although branding remains common in the United States, hot branding is prohibited in some countries.
Freeze branding is used to identify horses by applying a supercooled branding iron to the skin. The irons are typically made from copper and cooled using liquid nitrogen. Pressed against the skin for several seconds, the extreme cold damages pigment-producing cells, altering hair growth to produce a lasting mark. The brand is usually applied parallel to the mane, where it can be concealed by the hair.
I was invited to observe freeze branding by a worker affiliated with the United States Trotting Association (USTA), who coordinates identification procedures across multiple farms in the NY region. Foals were led into a stall alongside their mothers. Two farm workers restrained each foal while the USTA representative carried out the identification procedures, which included shaving the neck, applying the freeze brand iron, implanting a microchip, and collecting mane hairs for DNA records. These procedures typically take place when foals are between two and four months old.
Temporary Markings
Not all animal identification requires a manufactured tag or a permanent alteration to the body. Sometimes paint and other temporary markings can be used to tag an individual for short-term purposes. For example, spray paint applied on their backs or legs, marker written on rabbits’ ears, paper tags attached to live enclosures and labels on boxes used to transport dead animals.
Unlike other practices, a temporary marking may eventually fade, wash away, or be removed. Its usefulness is tied to the specific moment, the impermanence kind of confirms their short life span. I was struck by the directness of these methods: rather than attaching a separate identification device, a person uses the animal’s body itself as the place where information is written. The mark may be temporary, but it reflects the need to make the animal legible within an ongoing human activity.
Perhaps the least physically invasive form of identification, these temporary markings somehow felt the most dismissive. There is something about the normalcy of it, the way a scribble could be applied directly to a body as if it were a surface for notes, just further disregarding the animal itself.
Ear Notching
Ear notching is a form of permanent identification commonly used on pigs in farms and on rats in labs. The procedure involves removing triangular sections of the ear to create a pattern that identifies a pig’s litter and individual number. Ear notching is considered practical in pig farming because plastic ear tags can be torn out as pigs naturally root, burrow, and move against their surroundings. Ear notching is a permanent mutilation of the body; it cannot be removed. To my knowledge, animals do not receive pain medication during this procedure.
Throughout my fellowship, I repeatedly attempted to document this process, but no one was comfortable consenting to a camera being present during the procedure. I was repeatedly told that it was a simple procedure, “like using a hole punch.” Yet no one was willing to let me photograph it. People would express concern that the images might misrepresent the procedure. At the Maryland State Fair, in the live birthing area, I spoke with a former professor from Maryland’s swine program, who took the time to show me the notching tool and explain how to read the patterns cut into a pig’s ears, but would not allow me to observe the procedure itself.
At the fair, pregnant pigs were on public display for visitors to watch them give birth, and visitors were visibly captivated by their cuteness and charm. But the notching would usually take place after hours (because of the piglets' cries) behind a closed door. This contrast at the fair, where animal agriculture is presented as an educational experience, made the separation particularly striking: birth was made visible to the public, while the routine procedures performed on the newborns remained concealed.
The methods of identification vary, but they serve the same purpose: to make an animal easy to identify, trace, and link to its origin. But what does the act of numbering do to an animal as a living being? When does an animal’s identity become reduced to the information attached to their body? When does an animal lose their personhood and become a product? Is it at the moment of birth on a factory floor, or does this transformation happen gradually?
What stayed with me was the ordinary nature of these gestures—a number engraved into a tag, ink rubbed into a fresh wound, a notch of skin removed from an ear or a scribble written directly onto the body. Tagging can seem harmless as it is so normalized, yet it reveals the dominance humans exercise over animals’ bodies. Assigned numbers and marks take precedence over the ways we might otherwise recognize an individual, such as by their smell, appearance, voice, or behaviour. When animals are processed in such large numbers, their individual characteristics become invisible to the systems designed to identify and track them. The animal becomes one among millions, reduced to an assigned mark because numbers make bodies easier to manage at scale. What is efficient for human systems comes at the animals’ expense.
This work is part of Shay Salehi’s long-term project focused on researching tagging practices across wild and domesticated species, developing an archive of physical objects used in a range of contexts, from conservation to industrial agriculture. Follow the full project at shaysalehi.ca.
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