By Daniel Moran – Science Blog
Z16 walked about three times the distance from New York to Los Angeles, and he did it without a map, a passport or anybody’s permission.
He is a young bull elephant. In June 2023, staff from the conservation NGO Elephant Connection fitted him with a GPS collar north of Sioma Ngwezi National Park in western Zambia. Two years on, that collar logged close to 12,000 kilometres on foot, across four countries and through six national parks, as reported by Mongabay in December in a broader look at how elephants use southern Africa’s increasingly chopped-up ranges. The distance is the headline, but the shape of the route matters more.
Where he actually went
Z16 did not amble in circles. In early 2024 he left Zambia via Namibia’s Sobbe Corridor and neighbouring Mudumu National Park, crossed into northern Botswana, then dropped south through the Okavango Delta towards Makgadikgadi Pans. He appears to treat Makgadikgadi as home, which did not stop him taking a detour east to Hwange National Park, several hundred kilometres away in Zimbabwe.
Kerryn Carter, the wildlife biologist who founded Elephant Connection, told Mongabay that bulls seem to treat the arrival of the November rains as a starting gun. Her reading is that these bulls aren’t wandering, they’re returning to paths they’ve used for years.
A collar can only record position, never memory, so the pattern in the data is easier to establish than its cause. What shows up is consistent, directional travel by an animal that clearly knows where it is going, not proof of how or when he learned the way.
Bulls travel, family herds largely do not
The feel-good version of Z16’s story gets complicated once the rest of the tracking data comes in. Robin Naidoo of WWF and a large group of co-authors pooled almost four million GPS fixes from 291 collared elephants across all five KAZA countries for a 2024 paper in the Journal of Applied Ecology. Mongabay’s reporting on that same tracking effort put a number on the pattern. Nearly half of those 291 elephants visited more than one country over the years they were monitored, but only 36 per cent of those cross-border travellers were female. Female-headed herds make up more than 85 per cent of the region’s elephant population.
The gap widens further at fence lines specifically, which is a narrower question than crossing a border, since plenty of borders in this region run through open bush rather than wire. An earlier study by Naidoo and colleagues, published in Frontiers in Conservation Science in 2022, tracked more than 100 collared elephants specifically along the fenced stretch of the Namibia-Botswana border. There, the barrier proved complete for females: none of the animals collared on the Namibian side ever crossed into Botswana, or the reverse. Males did get through, though just seven bulls out of 21 accounted for most of it. One study, one border, one length of wire, not a universal law about elephants and fencing, but a firm result for this particular stretch.
Why the split? Carter puts it down to rivers and fences barely inconveniencing a bull, while cows travelling with calves rarely cross either. Naidoo offers a complementary explanation: females may treat big rivers as the natural edge of a home range. Their caution around fences, meanwhile, could reflect memories of years when those barriers were electrified and patrolled, or simply the fact that even a collapsing fence still stops a calf.
The corridor is four kilometres wide
Sobbe, the passage Z16 used, is roughly six kilometres long and four wide, tucked into the north-western corner of a community conservancy in Namibia’s long, narrow Zambezi region. That sliver of land links protected areas across Botswana, Zambia and Angola.
It sits inside KAZA, the Kavango-Zambezi Transfrontier Conservation Area, which spans about 520,000 square kilometres and five national jurisdictions. When the member states flew a synchronised aerial count in 2022, WWF reported an estimate of 227,900 elephants, broadly stable and a touch above the roughly 217,000 tallied in the previous survey.
Stable numbers in a shrinking amount of usable space are the pressure behind periodic calls for culling. Naidoo’s counter-argument is that corridors work as release valves, and need the same ongoing upkeep as any other piece of infrastructure, roads and pipes included.
Someone has to sleep in the field
Green lines on a conservation map run through places where people grow food.
Environmental anthropologist Emilie Köhler, who has done fieldwork at Sobbe since January 2023, and Michael Bollig documented that side of the ledger in the Review of Regional Research. One of the photographs from Köhler’s fieldwork, published alongside Mongabay’s report, shows a field near the corridor with no defence beyond a scatter of tin cans. Few smallholders can afford anything sturdier, so through the summer growing months, families camp out beside their maize, millet and sorghum, banging drums and lighting fires to keep raiding elephants moving.
Köhler and Bollig also traced how the corridor grew more contested as people settled and farmed closer to it through the late 2010s, and described the WWF-backed Wildlife Credits scheme introduced at Sobbe in 2018, which pays conservancies for verified conservation outcomes. A payment scheme like that only holds up if the money actually reaches the households absorbing the cost.
The arithmetic underneath all of this is awkward. A bull like Z16 makes the region look beautifully connected, because he can swim rivers, push through derelict fencing and simply keep walking. Breeding herds are the ones that actually determine where elephant density builds up, and those herds are, for now, staying largely put behind the same barriers.
Open a corridor and a wandering male will find it within a season. Getting a matriarch with a two-year-old to try the same route is the harder problem, and the one that decides whether any of this actually works.
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