Trade in wild animals and plants crosses borders constantly, in volumes that include timber, fish, pets, ornamental plants and medicinal ingredients. The regulatory system governing it works through lists and paperwork rather than outright prohibition.
Listings decide the rules
International agreements place species into tiers according to how threatened they are and how much trade contributes to that threat.
The strictest tier effectively bans commercial trade in wild-taken specimens. Middle tiers permit trade under permit, provided the exporting country judges it sustainable.
Moving a species between tiers is a political process as much as a scientific one, since exporting and importing states have different economic exposure to the outcome.
What a permit is supposed to prove
An export permit records that the specimen was legally obtained and that the export will not harm the survival of the species in the wild.
The second judgement is made by a scientific authority in the exporting country, and its rigour depends on that country's data and institutional strength.
Importing states are meant to check the paperwork on arrival, but customs officers handle enormous volumes and are not trained taxonomists.
Why captive breeding complicates everything
Animals bred in captivity are treated more permissively than wild-caught ones, which creates an incentive to declare wild animals as captive-bred.
The declaration is hard to disprove at a border. A juvenile parrot or reptile carries no visible mark of its origin, and paperwork can be produced to match.
Investigators therefore look at plausibility, checking whether a declared facility could biologically produce the numbers it claims given known breeding rates and stock.
Where enforcement actually happens
Seizures cluster at a small number of major transit hubs, because trafficking routes concentrate through airports and ports with high throughput and onward connections.
Detection relies on risk profiling, X-ray screening and detector dogs, all of which work better on bulk shipments than on small parcels carried by individual travellers.
Online sales have shifted much of the low-volume trade away from physical inspection entirely, moving the enforcement problem toward platform monitoring.
The demand side of the system
Regulation constrains supply, and supply constraints raise prices, which can make rare species more attractive to collectors rather than less.
Campaigns aimed at demand attempt to change what buyers want, and they work slowly, unevenly and only where the motivation for purchase is understood.
Because demand is culturally specific, a message that reduces buying in one market has little effect in another, which is why demand work is organised country by country.