Botany & Zoology
Welcome to Stellenbosch University

Prof. Hannes Van Wyk


Academic History



Field of study

Higher education institution



Physiology & Zoology

Univ of Stellenbosch




Univ of Stellenbosch




Univ of Stellenbosch




Univ of Cape Town




Name of employer

Capacity and/or type of work


Stellenbosch University

Technical Officer A, Department of Zoology


Stellenbosch University

Replacement Lecturer, Dept of  Zoology


National Museum, Bloemfontein

Curator of Herpetology


Stellenbosch University

Lecturer, Zoology


Stellenbosch University

Senior Lecturer, Zoology


Stellenbosch University

Associate Professor, Zoology

1997- 2009

Stellenbosch University

Professor, Zoology


Teaching: Undergraduate & Graduate

In the past I have taught a wide range of Zoology to Medical related degree courses
to first year students:

1st year: Introduction to human physiology; Introduction to Histology; Introduction to

2nd year: Doing Science (writing a scientific paper)

3rd year: Animal Physiology; Ecotoxicology (Endocrine disruption)

Hons: Environmental Physiology; Herpetology

Presently I am teaching:

Undergraduate, Biodiversity & Ecology Programme:

• Bio 144: Introduction to Cytology (link)
• BDE 254:Vertebrate Life (Reptiles) (link)
• BDE 334:Environmental Stress (link)

Postgraduate, BSc Honours Programme

• Stress Biology (link)
• Honours research project (link)

Course Coordination

Coordinator undergraduate courses

• Ecophysiology (1988-2003)
• Functional Biology (2001-2005)
• Introduction to Cell Biology (2006-
• Environmental Biology of Vertebrates (2007)

Coordinator: postgraduate courses

• Ecophysiology (1988-1990)
• Environmental Ecology of Vertebrates (1990-2003)
• Honours Programme Coordinator (2008, 2009)


• Animal Ethics
    –Vice Chair: Stellenbosch University Animal Ethics Committee
    –Member Science Faculty Animal Housing Committee
• Editor: African Zoology
• WRC Proposal Reviewer
• WRC Project Steering Committee Member
• NRF Peer Reviewer
• External Moderator
    –Univ of Cape Town
    –Univ of the Western Cape
    –Johannesburg University
• External Examiner, MSc & PhD
• Scientific Peer Reviewer for Scientific Journals                         

Current Postgraduate Supervision


Christoff Truter

Charles Babalola

Elindi Janse van Rensburg


Kandi Shivute

Edward Archer

Past Postgraduate Supervision


A. F. Flemming (1995) (P.leF.N. Mouton; JH van Wyk)
An analysis of the Agama atra complex (Sauria: Agamidae) in Namaqualand and southern Namibia.

M. J. Whiting (1998) (JH van Wyk; P.leF.N. Mouton; WE Cooper, USA)
Crevice life: the interplay between ecology and social behaviour in the lizard Platysaurus broadleyi

E. Hurter (2002) (JH van Wyk; EJ Pool)
Physiological and biochemical changes associated with vitellogenesis as biomarker for environmental estrogenic activity. 

S Clusella-Trullas, Drexel University, USA)(2005)(J Spotila, USA; JH van Wyk) (Won Best Dissertation Award)
Thermal ecology of melanistic and non-melanistic species of Cordylid lizards in the Western Cape of South Africa and effects of climate change on the distribution of these species

M. Esterhuyse (2008) (JH van Wyk; C Helbing, Victoria University, Canada)
Characterization of candidate genes related to estrogenic activity in Oreochromis mossambicus.

N. Swart (2009) (EJ Pool, UWC; JH van Wyk)
Estrogenicity biomarkers in the Mozambique tilapia (Oreochromis mossambicus)

D du Toit (2009) (P.leF.N. Mouton; JH van Wyk)
Effective conservation of melanistic lizard species in the Greater Cederberg Biodiversity Corridor


N. Badenhorst (1990) (P.leF.N Mouton;JH van Wyk)
An analysis of the Cordylus polyzonus complex (Reptilia: Cordylidae) in the south-western Cape

Y. Herselman (1991) (P.leF.N Mouton; JH van Wyk)
A revision of the taxonomic status of Pseudocordylus capensis (Reptilia: Cordylidae).  

H.C. Mackay (1992) (P.leF.N Mouton; JH van Wyk)
A comparative study of the cloacal complex in the lizard family Cordylidae.

I.G.Cordes (1994) (P.leF.N Mouton; JH van Wyk)
Conservation status of the lizard fauna associated with the atlantic ocean upwelling zone in the Saldanha-Langebaan area.  

E. Engelbrecht (D. Sadie; JH van Wyk)
The diet, thermoregulation and water balance of the geometric tortoise, Psammobates geometricus.   (1993)

L. Ruddock. (2000) Cum Laude (JH van Wyk; M Whiting (Wits)
The social behaviour of the giant girdled lizard, Cordylus giganteus.

L. Burger (2000-) (JH van Wyk)
Hormonal control of breeding glands in Xenopus laevis males with special reference to the effects of environmental anti-androgens.

E. Hurter (1999-2000) (JH van Wyk; EJ Pool) upgraded to PhD
The natural endocrine cycles associated with the female reproductive system in the aquatic frog Xenopus laevis, with special reference to the application of the yolk precursor, vitellogenin as a bio-indicator for detecting estrogenic contaminants in the environment

A. Strydom. (2001) (JH van Wyk; A Leslie)
The seasonal reproductive cycle of the fresh water turtle, Pelomedusa subrufa.

D. Theron (2001) (JH van Wyk)
The seasonal reproductive cycle in the soupfin shark, Galeorhinus galeus.  

A. Searby (2002) (JH van Wyk)
The histology of epidermal generation glands, with special reference to skin shedding cycles in selected cordylid lizards.  

W. Nkosi (Univ. of the North) (2002) N Heideman, Univ of the North; JH van Wyk
The seasonal reproductive cycles in the lacertid lizard Pedioplanis burcelli.

N. Coates (UPE)(2003) (M. Gehringer, UPE; JH van Wyk)
Development of an in vitro system using liver slices to investigate the toxic effect of microcystin on the liver.  

J.B. Hayes (2002) (JH van Wyk; C Boucher)
Assessment of fish bio-indicators of river health in rivers of the south-western Cape. 

S. Fourie (2005) (JH van Wyk; EJ Pool, UWC)
An Assessment of Water Quality and Endocrine Disruption Activities in the catchment of the Kuils River. 

C. Shuttleworth, C. (2006) (P. leF. N Mouton; JH van Wyk)
Ecological relationships between the armadillo lizard, Cordylus cataphractus, and the southern harvester termite, Microhodotermes viator. 

BSc-Hons (supervisor research projects):

Supervised or Co-supervised 26 honours research projects:

Sexual dimorphism and selective uptake of [3H]-testosterone by males, in the femoral glands of Cordylus cordylus (Sauria: Cordylidae).   L.S. Boeyens (1989).

Description of the contact zone between Cordylus cordylus and Cordylus niger at Mauritz Bay. A. van Heerden (1990)(with P.leF.N. Mouton).

A comparison of activity patterns of two closely relate cordylid lizard species, one melanistic, Cordylus niger and the other non-melanistic, C. cordylus. A van Heerden (1990) (with P.leF.N. Mouton).

Seasonal reproductive cycles in oviparous Platysaurus lizards, with special reference to Platysaurus capensis and P. guttatus minor.   S. Bosch (1991).

The urinary bladder of the lizard Cordylus polyzonus. H.C. Mackay (1991) (with P.leF.N. Mouton).

Comparative aspects of thermoregulation in the melanistic species, Cordylus niger and the non-melanistic species, C. cordylus. I.G. Cordes (1991) (with P.leF.N. Mouton). The chemical composition of the femoral gland secretion of the lizard, Cordylus cordylus.  F. Koegelenberg (1992).

The role of the gular area in visual communication in girdled lizards: an evolutionary perspective. E. Engelbrecht (1992) (with P.leF.N. Mouton).

An unique site of fat storage in the Drakensberg crag lizard, Pseudocordylus melanotus.   J.D. Julies (1992) (with P.leF.N. Mouton).

The reproductive cycle of the lizard Pseudocordylus capensis. R. Hartzenberg (1994).

Activity patterns and thermoregulation in the melanistic lizard, Cordylus niger.  P. Schneider (1996).

A description of early (hatchling stage) gonad development in the Nile crocodile (Crocodylus niloticus).  A. Strydom (co-supervisor A. Leslie)

The estrogenic effect of selected agricultural chemicals, using the African clawed frog (Xenopus laevis) as a bio-indicator. A. Strydom (co-supervisor: A Leslie)

Territoriality and Microhabitat selection in the Cape girdled lizard Cordylus cordylus (Sauria: Cordylidae). L. Ruddock. (1998)(co-supervisor M.I. Cherry).

Protein variation in the femoral gland secretions of the lizard, Cordylus giganteus. L. Ruddock. (1998).

A comparison of oxygen consumption rates at selected ambient temperatures between the melanistic cordylid lizard, C. niger and non-melanistic close-relative, C. cordylus.  E. Hurter (1999)( co-supervisor, P.leF.N. Mouton)

Seasonal variation in ovarian activity and plasma vitellogenin levels in natural, Xenopus laevis (Amphibia: Pipidae) populations in the Western Cape Province.  E. Hurter (1999)(co-supervisors: E. Pool & A. Leslie)

An assessment of estrogenic and anti-androgenetic activity in three selected sewage outlets in the Western Cape Province.  R. Albertus (1999)(co-supervisors: E. Pool & A. Leslie)

The in vitro effect of Heavy Metals on the Cellular Biology of small Mammals.  A. Chapman (1999)(co-supervisor with S. Reinecke & E. Pool)

Oreochromis mossambicus (Mozambique tilapia) as bioindicator species for detecting xenoestrogens in South African aquatic systems.   A. K. Faul (2000) (co-supervisor E.Pool)

Nuptial pads of Xenopus laevis as potential biomarkers for detecting anti-androgenic activity in aquatic systems.  L. Burger (2000) (co-supervisor E. Pool)

The effect of sex steroids and endocrine-disrupting contaminants on primary sexual differentiation in the African clawed frog, Xenopus laevis. M. Fraser  (2001)

Toxicological assessment of runoff-related pesticide contamination in Western Cape Rivers, using an in situ bioassay.  J.B. Hayes (2001) (co-supervisor: Dr R. Schultz)

Effects of the Pesticide Endosulfan on Thyroid Function in Developing Xenopus laevis tadpoles. K. Kalchmayr (2005)

The thermal biology of the armadillo girdled lizard, Cordylus cataphractus: thermal preference and variation in microhabitat thermal quality. C. Truter (2007)

The effect of a mixture of an insecticide, chlorpyrifos and a fungicide, vinclozolin on the endocrine systems of the African clawed frog, Xenopus laevis. E. Archer (2010).


Dr Alison Leslie Endocrine Disruption in water>1998 - 2000WRC, NRF and US funded

Dr Edmund Pool

Endocrine Disruption in water

1999 -2001

WRC, NRF and US funded

Dr Etienne Hurter

Endocrine Disruption in water


WRC and US funded

Dr Edmund Pool

Endocrine Disruption in water


WRC and US funded

Dr Marna Esterhuyse

Thyroid genes in fish as biomarkers for EDCs


WRC and  NRF funded