The first 72 hoursafter a death.

Living cells need oxygen and nutrients delivered by blood. When an animal dies, that delivery stops, and the tissue begins to run down its own internal reserves. Skin cells are relatively hardy compared with, say, neurons, which is one reason skin is the tissue almost always used for banking. But hardy is not indefinite. As oxygen runs out, cells switch to less efficient ways of generating energy, waste products accumulate, and eventually enough of them stop functioning that a biopsy taken from that tissue will not yield a living culture, however carefully it is handled afterward.

The precise number of hours varies with temperature, the animal, and the tissue, but as a working rule we ask that a biopsy be taken and refrigerated within 24 to 48 hours of death, and that it reach a laboratory within 72. We describe this as urgent rather than impossible, because it usually is not impossible – but every hour that passes narrows the odds, and we will not promise a result once too much time has gone by.

The single most important action in this window is refrigeration, not freezing. A body or tissue sample kept at refrigerator temperature, around 4 °C, slows the metabolic decline sharply without the ice damage that home freezing would cause. Placing a sample in a domestic freezer, out of a wish to be thorough, is one of the more common ways a viable biopsy is lost, because ice crystals formed without a cryoprotectant and a controlled cooling rate destroy the very cells someone was trying to save.

In practice this means: keep the animal, or the tissue once a veterinarian has taken it, cold and out of direct contact with ice, and arrange transport as soon as possible. We coordinate this by WhatsApp at any hour, and can usually direct a local veterinarian on what to take and how to package it even before our own courier arrangements are confirmed.

The procedure itself is minor. A veterinarian takes one or more small pieces of skin, typically from the ear or flank, using a sterile punch biopsy tool, under local anaesthetic if the animal is alive, or without anaesthetic if the sample is taken shortly after death. The tissue goes into a transport medium we supply or specify, which keeps it moist, nourished, and at the right pH during transit. No advanced equipment is needed at the point of collection; almost any veterinary clinic can do this correctly with brief guidance from our laboratory.

From there the tissue travels to whichever of our laboratories – Abu Dhabi, Bahrain, or California – is closest, or best positioned for the fastest transit. Shipping between our laboratories is included in the arrangement; the cost that follows is for cell banking itself, quoted at 5,000 USD within the UAE or 6,500 USD across the wider GCC, plus 500 USD a year for cryostorage once the line is established. Once the tissue arrives, culturing follows the same process described in fibroblasts: explants placed in a dish, cells allowed to migrate out, and growth monitored over the following one to two weeks.

The 72-hour figure is a guideline built from how quickly skin tissue typically loses viability once circulation stops, adjusted for the realities of transport across the distances our laboratories cover. It is not a fixed rule that closes at hour 73; some biopsies taken slightly later still succeed, and some taken earlier still fail, depending on ambient temperature, how the animal died, and how carefully the tissue was handled in between. We give a firm number because a firm number is more useful in a moment of shock than a vague range, but we would rather a family call us at hour 80 to ask than assume the option has already closed.

It is worth separating urgency from panic. A 72-hour window is real, but it does not mean a family has to make every decision about cloning, stem cells, or long-term plans within that time. The only decision that has to be made quickly is whether to preserve a biopsy at all. Everything downstream – whether to pursue genetic testing, whether to consider a cloning attempt years later, whether to do nothing further – can wait, sometimes for years, once cells are safely banked and split between two cities as described in two cities.

We say this deliberately because grief and urgency together tend to push people toward decisions that deserve more time. The biopsy is the only irreversible clock. A completed, tested deposit removes that clock entirely and returns the rest of the decision to whenever the owner is ready to think about it.

This sequence has held for animals across the region our laboratories cover, from Abu Dhabi outward to Bahrain and toward the upcoming Doha and Riyadh sites, as well as for arrangements involving horses, camels, dogs and cats. It does not apply to birds, where we offer preservation only, without downstream cloning; details are set out separately in the falcon-specific article on the limits of cloning.