An adult
male lion ("Miles" or Xpl-16) of the Ugab Pride was selected
as the ideal candidate for a GPS collar. He was first radio-collared
in May 2001 and has been monitored ever since. On 23 April 2008
he was immobilised and fitted with the only Satellite GPS collar.
Known
home range of Xpl-16 prior to fitting the Satellite GPS collar
Fitting
of the Satellite GPS collar
Efforts
to dart and radio-collar new Ugab males A
marathon effort was required to locate and dart one of the lions
that killed Xpl-16. Their tracks were followed for hundreds of kilometres
across the broken Ugab terrain and eleven consecutive nights were
spent sitting-up and waiting for a chance to dart them. The tracks
of the two males were measured and studied in detail, and it was
possible to distinguish between the two individuals by the size
and shape of their tracks, and by the manner of walking (foot placement
& sequence). On the 11th night a sound playback of the roar
of “Miles” was used. This appeared to have tricked the
two males. They charged towards the speaker, arguably looking for
“Miles” (the lion they killed a week before), and gave
me an opportunity to dart one of them.
Comparing
the spoor and pads of the right hind foot
Sound
file of Xpl-16's roar
00:30
(64Kb)
Xpl-16
died on 15 August 2008 On
15 Aug 2008 the satellite GPS collar of Xpl-16 reported that the
mortality beacon inside the collar had been triggered. The mortality
beacon was programmed to activate after 150 minutes of no movement.
Upon receiving the message an effort was made to locate the lion
and investigate. However, much of the lower Ugab River was not drivable
because of the high rainfall earlier in the year and the terrain
outside the riverbed was extremely rugged. After five days of getting
stuck, trying different routes, and building river crossings and
pathways over gorges, the death of Xpl-16 was confirmed. Two full
days were spent studying the tracks and other signs to reconstruct
the events that caused his death. It was not an easy task because
several days had passed and there had been strong east winds.
Images
of the rugged terrain
First view of the carcass of "Miles"
Closer inspection to determine the cause of death
Cause
of Death - Conclusion
1)
On 10 Aug 2008 Xpl-16 killed an oryx and was feeding on it.
2)
Sometime between 11 and 13 Aug 2008 a group two adult male lions
arrived at the scene.
3)
An extensive territorial battle between Xpl-16 and the new
males enfolded.
4)
At one point during the battle, Xpl-16 succeeded in displacing
the males and chased them >1 km south of the Ugab River.
5)
But the males returned and during the night of 14th Aug, got
the better of Xpl-16.
6)
Xpl-16 tried to get away from the males by running up a near-vertical
cliff (see illustration below).
7)
One of the males caught up with him on the cliff - 20 metres
above the ground – and they came crashing down.
8)
There is evidence of an extensive battle: deep scrape marks
and blood stains in the soil.
9)
Xpl-16 was mortally wounded during this battle and died sometime
during the late afternoon on 15th Aug 2008.
Signs
of the battle in the sand
Xpl-16
fled up cliff (white arrows). Caught by males (X). Falling
to ground (red arrow).
Chunks
of blood-drained sand
Xpl-16
lay in the shade (right) earlier on 15 Aug.
Extensive
abdominal wound - notice brand
Collecting
necropsy samples
Chronology
of NEWS entries
27
Aug
2008:
Killer lions hoodwinked. A
couple of days ago, I recalled filming “Miles” roaring
in the Springbok River, and decided to try and trick the lions.
Similar to human voices, the roars of lions are unique and they
recognise different individuals. I captured the sound file on the
computer, cleaned it up with sound editing software, and was ready
to con the lions into thinking that “Miles” is still
alive. Shortly after midnight this evening, the ploy paid off when
the two male lions responded to the sound playbacks from several
kilometres away. They roared continuously and approached the vehicle
aggressively. I was able to dart one of the lions and fitted a GPS
collar (see above for more details & listen to the sound file).
20
- 26 Aug
2008:
Hot pursuit. The
unexpected death of Xpl-16 ("Miles") has left a vacuum
in the Desert Lion study. Not only did the satellite GPS collar
provide high quality data on the movements of the Ugab Pride, but
also “Miles” was the only radio-collared lion. This
is a significant loss because the Ugab Pride occupies the southern
frontier of the Desert lion distribution, and they are thus most
likely to disperse, in search of new territories. It is essential
to capture and radio-collar at least one of the new lions, before
they disappear in the vast and broken Ugab terrain. The best technique
under these conditions is one of tracking their spoor in the daytime
to try and catch-up with them, and then using sound playbacks and
bait to attract them at night. Including this evening, I’ve
sat up for 10 nights, and covered hundreds of kilometres following
their tracks, without seeing or even hearing a lion.
Lion
A - right hind foot.
Search
for the lions west of the Brandberg.
Lion
B- left hind foot.
Finding
new routes whilst tracking the lions.
Distribution
of the nighttime calling stations, along the Ugab River (map
= 100 km across).
15
- 21 Aug
2008:
Ugab male "Miles" died. On
15 Aug the email sent by the satellite GPS collar of Xpl-16, the
Ugab male lion, revealed that the mortality beacon inside the collar
had been triggered. I dropped everything and set off to investigate.
However, much of the lower Ugab River was not drivable because of
the high rainfall earlier in the year and the terrain outside the
riverbed is extremely rugged. At one point I considered walking
(32 km), but I was not convinced that “Miles” was dead;
the mortality beacon had stopped and it was possible that the collar
was faulty. After five days of getting stuck, trying different routes,
and building river crossings and pathways over gorges, I finally
reached the destination. Disappointingly the collar was not faulty
and I located the carcass of Xpl-16. Another two days were spent
studying the tracks and other signs to reconstruct the events that
caused his death.
Real-time
animations
The movement patterns of "Miles" (Xpl-16) in the Ugab
River are presented below using Flash animations to represent real-time
events. Click on the PLAY button to start the animation.
The timeline is constant at 2.5 seconds per day (24 hrs). When the
red dot moves quickly across the screen, it accurately represents
the speed at which the lion covered vast distances. A summary
of the actual distances traveled per day is listed in a separate
table.
