Age and development in the red hartebeest (Alcelaphus caama), from photos

@christiaan_viljoen @dewald2 @matthewinabinett @jacqueline_llerena @simontonge @paradoxornithidae @tonyrebelo

The relationship between age and appearance is potentially informative in any species of ungulate. However, it is particularly so in the red hartebeest (Alcelaphus caama), because

• the angularity of the horns means that their shapes change progressively as they grow,
• the colouration of the pelage undergoes progressive changes from birth to full maturity, and
• a given mother can be seen followed by up to three offspring (compared to only at most one in the case of closely-related and ecologically comparable species of Damaliscus, of similar body size).

Please see the illustrations in https://www.researchgate.net/publication/316165747_Focus_on_the_Red_Hartebeest_Alcelaphus_buselaphus_caama

Newborn

https://www.dreamstime.com/addo-elephant-national-park-south-africa-image201995623
https://www.dreamstime.com/red-hartebeest-calf-southern-african-savanna-image145519702

INFANTS HIDE FOR TWO WEEKS, helping to explain why there are so many photos of infants slightly older than 2 weeks, as follows.

2-3 weeks

https://www.inaturalist.org/observations/34703540
https://stock.adobe.com/images/id/6354853?tduid=86f6bb255d68643c6d65a89810a8b212&as_channel=affiliate&as_campclass=redirect&as_source=arvato
https://www.agefotostock.com/age/en/details-photo/red-hartebeest-alcelaphus-buselaphus-at-waterhole-kalahari-botswana-africa/ISO-IS09B64Z9
https://www.inaturalist.org/observations/127790132
https://www.dreamstime.com/red-hartebeest-calf-red-hartebeest-calf-wet-rain-shower-southern-african-savanna-image107666150
https://www.dreamstime.com/red-hartebeest-calf-southern-african-savanna-image145519842
https://www.dreamstime.com/stock-image-baby-red-hartebeest-antelope-image13753251
https://www.dreamstime.com/royalty-free-stock-images-baby-red-hartebeest-antelope-mom-image11720999
https://www.dreamstime.com/stock-photo-juvenile-red-hartebeest-southern-african-savanna-image93776386
https://www.dreamstime.com/stock-photo-juvenile-red-hartebeest-southern-african-savanna-image93776491
https://stock.adobe.com/images/red-hartebeest-alcelaphus-buselaphus-caama-or-a-caama-juvenile-young-baby-antelope-portrait-with-one-eye-shut-as-if-winking/421088757?as_campaign=ftmigration2&as_channel=dpcft&as_campclass=brand&as_source=ft_web&as_camptype=acquisition&as_audience=users&as_content=closure_asset-detail-page
https://www.alamy.com/a-red-hartebeest-alcelaphus-buselaphus-caama-calf-or-small-baby-antelope-running-to-catch-up-image213086330.html
https://www.inaturalist.org/observations/127619182

BY ONE MONTH OLD, the horns are not yet noticeable, but body mass has doubled since birth.

1 month

https://www.agefotostock.com/age/en/details-photo/red-hartebeest-alcelaphus-buselaphus-young-kgalagadi-transfrontier-park-kalahari-desert-south-africa/YD4-2933940
https://www.pikist.com/free-photo-sqetz
https://www.dreamstime.com/red-hartebeest-calf-southern-african-savanna-image145519513
https://www.dreamstime.com/red-hartebeest-calf-southern-african-savanna-image145519750
https://www.alamy.com/alert-young-kudu-calf-image65992949.html?imageid=F7972E69-9122-4D9B-A1DC-A5CB20701C31&p=40848&pn=2&searchId=b0dfc14786b5fa6ae25dfd03aa754a21&searchtype=0
https://www.inaturalist.org/observations/80401764

2 months
https://www.dreamstime.com/red-hartebeest-calf-southern-african-savanna-red-hartebeest-calf-image138194762
https://www.dreamstime.com/royalty-free-stock-photography-red-hartebeest-standing-open-field-calf-image29300867
https://www.dreamstime.com/royalty-free-stock-photos-red-hartebeest-standing-open-field-calf-image29300908

3 months

https://www.pond5.com/stock-footage/item/36490409-red-hartebeest-calf
https://www.inaturalist.org/observations/86069654
https://www.inaturalist.org/observations/22357084

The appearance of suckling juveniles of this age can be seen

• in https://www.shutterstock.com/video/clip-1092106509-red-hartebeest-female-suckling-calf-mountain-zebra, and
• from 3:15 in https://www.youtube.com/watch?v=XJF90jV-T0A.

4 months

https://www.dreamstime.com/juvenile-red-hartebeest-calf-mist-juvenile-red-hartebeest-calf-misty-morning-addo-elephant-park-south-africa-image228762287
https://www.dreamstime.com/hartebeest-female-calf-kgalagadi-transfrontier-park-south-africa-specie-alcelaphus-buselaphus-family-bovidae-hartebeest-image240044359
https://www.dreamstime.com/hartebeest-female-calf-kgalagadi-transfrontier-park-south-africa-specie-alcelaphus-buselaphus-family-bovidae-hartebeest-image240044372
https://www.dreamstime.com/stock-photo-juvenile-red-hartebeest-southern-african-savanna-image93776768
https://www.dreamstime.com/royalty-free-stock-image-hartebeest-red-animal-moms-cow-her-calf-drinking-water-photo-taken-game-ranch-namibia-africa-image30435926
https://www.robertharding.com/preview/764-3238/young-red-hartebeest-alcelaphus-buselaphus-addo-elephant-national/
https://www.robertharding.com/preview/764-5930/red-hartebeest-alcelaphus-buselaphus-cow-calf-addo-elephant/
https://www.alamy.com/stock-photo-red-hartebeest-alcelaphus-caama-50919189.html?imageid=04C1D099-3F70-4A05-8C57-E2ABED2E5322&p=170574&pn=1&searchId=9602590878ee9911fc12a6e1486d6e22&searchtype=0
https://www.alamy.com/young-red-hartebeest-alcelaphus-buselaphus-running-in-grassland-mountain-zebra-national-park-south-africa-image472233605.html?imageid=AB82AC72-0091-4A2F-803B-421A23B37322&p=70019&pn=1&searchId=9602590878ee9911fc12a6e1486d6e22&searchtype=0

BY SIX MONTHS,

• body mass is half that of mature females,
• the pedicel at the base of the horns has reached its full proportional length,
• the horns remain simple short spikes, and
• the hindquarters have acquired their conspicuously pale feature, but the eyes have become masked.

6-7 months

https://www.flickr.com/photos/arthur_chapman/7600869392/in/photostream/
https://stock.adobe.com/fi/search?k=%22red+hartebeest%22&asset_id=368460805
https://www.inaturalist.org/observations/103543206
https://www.inaturalist.org/observations/96453015
https://www.inaturalist.org/observations/32475264
https://www.inaturalist.org/observations/24431929
https://stock.adobe.com/fi/search?k=%22red+hartebeest%22&asset_id=510930262
https://www.inaturalist.org/observations/87422880

8 months

https://pixabay.com/photos/red-hartebeest-antelope-hartebeest-4114705/
https://stock.adobe.com/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=hartebeest&order=relevance&safe_search=1&limit=100&search_page=14&search_type=pagination&get_facets=0&asset_id=480986151
https://stock.adobe.com/fi/search?k=%22red+hartebeest%22&asset_id=411186967
https://stock.adobe.com/fi/search?k=%22red+hartebeest%22&asset_id=480174251
https://www.inaturalist.org/observations/84420586
https://www.inaturalist.org/observations/33775370
https://www.agefotostock.com/age/en/details-photo/hartebeest-alcelaphus-buselaphus-in-the-early-morning-etosha-national-park-namibia-africa/IBK-1082236

ABOUT NINE MONTHS OLD, THE HORN TIPS TOUCH EACH OTHER before growing apart again

9 months

https://www.pikist.com/free-photo-siesm
https://pixabay.com/photos/red-hartebeest-hartebeest-antelope-4757941/
https://www.dreamstime.com/stock-images-red-hartebees-front-dead-trees-image29369634
https://www.inaturalist.org/observations/121590665
https://www.inaturalist.org/observations/94453196
https://www.inaturalist.org/observations/18412388
https://www.inaturalist.org/observations/7274278
https://www.agefotostock.com/age/en/details-photo/hartebeest-alcelaphus-buselaphus-in-the-early-morning-etosha-national-park-namibia-africa/IBK-1082234

10 months

https://www.shutterstock.com/image-photo/female-red-hartebeest-walking-her-young-1475515883
https://www.dreamstime.com/royalty-free-stock-photo-red-hartebees-family-young-calf-standing-green-fields-image35903145
https://stock.adobe.com/fi/search?k=%22red+hartebeest%22&asset_id=198816863
https://www.inaturalist.org/observations/63478415
https://www.inaturalist.org/observations/42748058
https://www.inaturalist.org/observations/35942310
https://www.inaturalist.org/observations/20177206
https://www.shutterstock.com/image-photo/red-hertbeest-savannah-alcelaphus-caama-200785607

The following shows adult female with 10 month-old male, probably its son:
https://www.shutterstock.com/image-photo/adult-hartebeest-her-adolescent-young-kalahari-113169034

AT ONE YEAR OLD, THE HORN-TIPS BECOME HORIZONTAL. The dark patches on shoulder and ventral part of haunch are not yet fully-developed.

12 months

female:

https://stock.adobe.com/fi/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=%22red+hartebeest%22&order=relevance&safe_search=1&limit=100&search_page=2&get_facets=0&search_type=pagination&asset_id=367151611
https://www.inaturalist.org/observations/117569311
https://www.inaturalist.org/observations/54496645
https://www.inaturalist.org/observations/24431982

male:

https://www.shutterstock.com/video/clip-11340560-red-hartebeast-4k-footage-namibian-savannah
https://es.123rf.com/photo_91529230_an-alert-red-hartebeest-antelope-on-the-african-grassland.html
https://www.agefotostock.com/age/en/details-photo/red-hartebeest-close-up/SLR-IS098Y6W3
https://www.inaturalist.org/observations/104693518
https://stock.adobe.com/fi/search?k=%22red+hartebeest%22&asset_id=63615660
https://www.inaturalist.org/observations/35819422

1.5 years, female

https://www.agefotostock.com/age/en/details-photo/red-hartebeest-walking-in-grass/SLR-IS098Y6W2
https://www.inaturalist.org/observations/116586348

1.5 years, male

https://www.agefotostock.com/age/en/details-photo/red-hartebeest-or-khama-alcelaphus-buselaphus-caama-ithala-national-park-republic-of-south-africa/D17-1788911

AT TWO YEARS OLD, THE FOREHEAD FINALLY BECOMES DARK

Estes (1991, page 139) states: "Male hartebeests often accompany their mothers for up to 2.5 years, a year longer than other alcelaphines, yet mature no later than wildebeests, at 3-4 years (Gosling, 1974). The basis of this unusual arrangement is continuous breeding: female hartebeests calve every 9-10 months (gestation 8 months), too early for the last calf to become independent".

2 years

https://www.imago-images.com/st/0152431666
https://stock.adobe.com/fi/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=%22red+hartebeest%22&order=relevance&safe_search=1&limit=100&search_page=2&get_facets=0&search_type=pagination&asset_id=63615658
https://stock.adobe.com/fi/search?k=%22red+hartebeest%22&asset_id=522906968
https://www.inaturalist.org/observations/40968903
https://www.agefotostock.com/age/en/details-photo/red-hartebeest-alcelaphus-buselaphus-caama-adult-male-standing-in-the-high-grass-kgalagadi-transfrontier-park-northern-cape-south-africa-africa/ZI6-3572633
https://www.inaturalist.org/observations/52142300

AT 2-2.5 YEARS OLD, FEMALES REACH SEXUAL MATURITY

Males become sexually mature at about 3 years, but socially mature only some 5 years later

3 years, female

https://www.inaturalist.org/observations/201786
https://www.agefotostock.com/age/en/details-photo/red-hartebeest-alcelaphus-buselaphus-caama-adult-running-across-a-dirt-road-close-of-day-kgalagadi-transfrontier-park-northern-cape-south-africa-africa/ZI6-3564222
https://www.inaturalist.org/observations/95198707
https://www.inaturalist.org/observations/27721560

AT THREE YEARS OLD

• FEMALES BEAR THEIR FIRST INFANT, and
• MALES SURPASS THE BODY MASS OF THEIR MOTHERS

3 years, male

https://www.inaturalist.org/observations/103543206
https://www.agefotostock.com/age/en/details-photo/kuhantilope-red-hartebeest-alcelaphus-buselaphus-etosha-namibia/ZON-8871375
First photo in https://www.inaturalist.org/observations/62680448

5 years, female

https://www.agefotostock.com/age/en/details-photo/red-hartebeest-alcelaphus-caama-this-antelope-stands-1-5-metres-tall-at-its-shoulder-and-can-weigh-up-to-200-kilograms-red-hartebeests-live-in-open-forests/SPL-Z956-0277

5 years, male

https://www.agefotostock.com/age/en/details-photo/red-hartebeest-alcelaphus-buselaphus-mountain-zebra-national-park-south-africa-africa/RHA-764-988
https://stock.adobe.com/fi/search?filters%5Bcontent_type%3Aphoto%5D=1&filters%5Bcontent_type%3Aillustration%5D=1&filters%5Bcontent_type%3Azip_vector%5D=1&filters%5Bcontent_type%3Avideo%5D=1&filters%5Bcontent_type%3Atemplate%5D=1&filters%5Bcontent_type%3A3d%5D=1&filters%5Bcontent_type%3Aaudio%5D=0&filters%5Binclude_stock_enterprise%5D=0&filters%5Bis_editorial%5D=0&filters%5Bfree_collection%5D=0&filters%5Bcontent_type%3Aimage%5D=1&k=%22red+hartebeest%22&order=relevance&safe_search=1&limit=100&search_page=2&get_facets=0&search_type=pagination&asset_id=113541552
https://www.inaturalist.org/observations/116565592
https://www.inaturalist.org/observations/11076946
https://www.agefotostock.com/age/en/details-photo/red-hartebeest-alcelaphus-buselaphus-standing-in-the-savanna-side-view-south-africa-western-cape-karoo-national-park/BWI-BS443380
https://www.agefotostock.com/age/en/details-photo/red-hartebeest-alcelaphus-caama-kgalagadi-transfrontier-park-kalahari-south-africa/EEA-SS2255514

10 years, female

https://www.agefotostock.com/age/en/details-photo/red-hartebeest-alcelaphus-buselaphus-kgalagadi-transfrontier-park-south-africa/YD4-1629907

AT TEN YEARS OLD, MALES REACH THEIR PRIME becoming noticeably darker than mature females

10 years, male

https://www.inaturalist.org/observations/102666578
https://www.inaturalist.org/observations/99463527
https://www.inaturalist.org/observations/57816678
https://www.inaturalist.org/observations/47862767
https://www.inaturalist.org/observations/11111379

12 years, male

https://www.inaturalist.org/observations/117556686
https://www.inaturalist.org/observations/49832745
https://wildlifesafari.info/hartebeest_red.html

15 years, male

https://www.inaturalist.org/observations/86376921
https://www.inaturalist.org/observations/66735467

DISCUSSION

The colouration on the hindquarters is far more precocial than that on the head.

The bleeze on the hindquarters (including darkness of the tail) appears (https://www.inaturalist.org/observations/18676884) long before the full set of dark markings on the head appears (https://stock.adobe.com/fi/search?k=%22red+hartebeest%22&asset_id=522906968).

The ontogenetic sequence of colouration on the head is intriguing.

In infants, the head is plain except for dark on the lower lip, pale on the anterior surface of the ear pinnae, and pale immediately around each eye (https://stock.adobe.com/images/red-hartebeest-alcelaphus-buselaphus-caama-or-a-caama-juvenile-young-baby-antelope-portrait-with-one-eye-shut-as-if-winking/421088757?as_campaign=ftmigration2&as_channel=dpcft&as_campclass=brand&as_source=ft_web&as_camptype=acquisition&as_audience=users&as_content=closure_asset-detail-page and https://www.agefotostock.com/age/en/details-photo/red-hartebeest-alcelaphus-buselaphus-young-kgalagadi-transfrontier-park-kalahari-desert-south-africa/YD4-2933939).

By six months old, the pale around each eye has largely been replaced by a dark patch (https://www.agefotostock.com/age/en/details-photo/red-hartebeest-alcelaphus-buselaphus-standing-in-the-savanna-side-view-south-africa-western-cape-karoo-national-park/BWI-BS443379). This small-scale 'mask' remains throughout life.

However, dark on the forehead takes about another 1.5 years to appear (https://www.shutterstock.com/image-photo/two-red-hartebeest-looking-camera-early-1712872699).

It may be worth pondering why dark on the tail is present already at birth (https://www.istockphoto.com/photo/red-hartebeest-and-calf-gm1216185417-354538365?phrase=juvenile%20red%20hartebeest), whereas dark on the forehead is delayed until adolescence.

I hypothesise that this is because the colouration on the hindquarters is adaptive mainly against predation, whereas the colouration on the head is adaptive mainly socially.

Posted on October 12, 2022 02:48 PM by milewski