The vast majority of content published on Walrus Network was compiled from online sources, including but not limited to; official press releases, scientific literature, periodical publications, annual reports, books and magazines, social media, online forums, and so on. Other information is obtained via personal communication with animal care staff, veterinarians, public relations team members, and others involved in the zoological field.
Walrus Network operates on a sightings-based headcount system to approximate the minimum number of currently living individuals in captivity; this system is especially useful for facilities which publish little to no information on their walruses -- it enables me to become familiar enough with certain individual animals to be able to photo-identify them, which allows a higher probability of confirming the status of that animal and tracking any transfers that may take place which would have otherwise gone unannounced and undetected. Sightings and headcounts are done via one of two methods: counting the maximum number of individual walruses sighted within a single photo or video, or by counting the number of identifiable individuals sighted at a facility.
I take a thorough annual census of the captive walrus population every year during the month of December; When an individual walrus is not accounted for via either visual sighting or written/spoken record within a full calendar year, that animal is transitioned into "unknown" status. It will then be placed into the "past inventory" section of the facility page which it was last known to reside at, and will remain marked as unknown until it is confirmed to be either alive or deceased.
In many cases, walrus names will be transliterated into English from their native language (for example, a walrus may be listed here as 'Aosika' instead of the likely intended name of 'Oscar'). These overtly literal translations make it easier for me to identify individuals when translation services may offer up multiple different versions of a single name. Exceptions to this will be made when an individual is well enough known, or if the intended translation of its name comes into common use; for example, 'Rokku' becomes 'Rock'.